SB 

211 


UC-NRLF 


A  Study,  by  the  Crop  Survey  Method,  of 

"Factors  Influeneing  the  Yield 
-•;,  of  Potatoes 


A  THESIS 

PRESENTED  TO  THE  FACULTY  OF    THE    GRADUATE    SCHOOL   OF 

CORNELL  UNIVERSITY  FOR  THE  DEGREE  OF 

'DOCTOR  OF  PHILOSOPHY 


BY 


EARLE  VOLCARTIHARDENBURG 


Published  as  Memoir  57 
Cornell  University  Agricultural  Experiment  Station,  June  1922. 


A  Study,  by  the  Crop  Survey  Method,  of 

Factors  Influencing  the  Yield 

of  Potatoes 


A  THESIS 

PRESENTED  TO  THE  FACULTY  OF    THE    GRADUATE    SCHOOL   OF 

CORNELL  UNIVERSITY  FOR  THE  DEGREE  OF 

DOCTOR  OF  PHILOSOPHY 


BY 

EARLE  VOLCARTJHARDENBURG 


Published  as  Memoir  57 
Cornell  University  Agricultural  Experiment  Station,  June  1922. 


517499 


CONTENTS  '  '•  ' 

't       '  ,    '"  >  '  '        «        •  •  PAGE 

The  crop  survey  as  a  method  of  research ....'.','.  .'.'. .  ;   , ... ,  .  .'./.  •  'J;  • .,.;.  \ . '.  -• 1145 

Biometry  as  applied  to  crop-survey  data '..'.' 1147 

The  taking  cf  records ' 1147 

Description  of  regions  surveyed 1148 

Long  Island 1149 

Steuben  County ..:..- 1153 

Monroe  County 1154 

Franklin  and  Clinton  Counties 1155 

Method  of  studying  survey  data 1156 

The  study  of  factors 1157 

Climate 1157 

Elevation 1159 

Crop  rotation 1162 

Value  of  land. . . . '. 1166 

Soil ' 1169 

Plowing , 1171 

»     Time  of  plowing 1171 

Depth  of  plowing .• 1173 

Manure  and  fertilizer 1177 

Home-mixed  fertilizers 1179 

Quantity  and  value  of  fertilizer 1180 

Manure  and  fertilizer  used  in  the  four  regions 1182 

Analysis  of  fertilizer 1188 

Method  of  applying  fertilizer 1191 

Use  and  influence  of  lime  on  potato  land 1196 

Adaptation  and  yield  of  varieties 1197 

Source  of  seed .' 1205 

Sun-sprouting  of  seed 1208 

Chemical  treatment  of  seed 1210 

Interval  between  cutting  and  planting. 1211 

Dusting  cut  seed 1214 

Type  of  seed 1215 

Large  as  compared  with  small  tubers  for  seed 1215 

Whole  as  compared  with  cut  seed 1216 

Large  as  compared  with  small  seed  pieces 1217 

Number  of  eyes 1220 

Types  of  seed  used  in  the  four  regions  surveyed .  . 1221 

Relation  of  amount  of  seed  to  yield 1224 

Date  of  planting 1231 

Hand  as  compared  with  machine  planting t 1232 

Checkrow  as  compared  with  drill  planting 1234 

Depth  of  planting 1237 

Depth  of  cultivation ; 1242 

Ridge  as  compared  with  level  culture 1244 

Frequency  of  cultivation .' .    1246 

Spraying .    1255 

Relation  of  date  of  harvest  to  yield 1263 

Method  of  harvesting  in  the  four  regions  surveyed 1265 

Types  of  storage  in  the  four  regions  surveyed 1269 

Length  of  storage  period 1269 

Summary 1270 

Conclusions 1272 

Author's  acknowledgment 1273 

Bibliography 1274 

Survey  blank 1280 

1139 


A  STUDY,  BY  THE  CROP  SURVEY  METHOD,  OF  FACTORS 
INFLUENCING  THE  YIELD  OF  POTATOES 


A    STUDY,   BY  THE  CROP    SURVEy  METHOD,  'OF;  FACTORS 
INFLUENCING  THE  YIELD  OF  POTATOES1" 

EARLE  V.  HARDENBURG 

Almost  from  the  date  of  their  establishment,  practically  all  state  and 
federal  experiment  stations  in  this  country,  as  well  as  many  foreign 
stations,  have  tested,  by  diverse  methods,  the  relative  influences  of  factors 
affecting  the  yield  of  potatoes.  A  review  of  the  abundant  literature  of 
the  subject  shows  that  a  majority  of  these  tests  concern  the  influence  of 
seed  and  fertilizers  on  yield.  This  fact,  further  substantiated  by  the 
results  of  the  study  herein  reported,  indicates  that,  with  the  exception  of 
climate  and  soil,  seed  and  fertilizers  are  the  most  vital  factors  affect- 
ing yield.  Because  of  the  widely  differing  environmental  conditions  under 
which  the  tests  have  been  conducted,  it  is  possible  in  only  a  limited  degree 
to  draw  definite  conclusions  from  a  summary  of  the  results.  Furthermore, 
a  large  part  of  the  literature  fails  to  supply  much  detailed  information 
as  to  the  methods  used  in  the  experiments,  and  gives  little  if  any  considera- 
tion to  factors  affecting  yield  other  than  the  one  principally  concerned 
in  the  respective  tests.  This  means  that  most  of  the  evidence  available 
to  date  is  of  only  limited  application. 

A  comparison  of  the  conclusions  reached  and  the  recommendations 
made  by  experiment  stations,  with  those  warranted  by  actual  practice  as 
found  on  farms  in  a  potato-growing  region,  is  therefore  of  considerable 
value.  Such  a  comparison  is,  to  some  extent,  made  possible  by  the 
use  of  the  survey  method  of  collecting  and  studying  data  on  the  influ- 
ences affecting  the  yield  of  potatoes.  The  survey  method  has  accordingly 
been  applied  to  the  study  of  such  factors  in  several  potato  sections  of 
New  York,  and  the  results  are  herein  compared  with  those  obtained 
experimentally.  As  an  additional  check  on  the  conclusions  drawn, 
the  biometrical  method  as  applied  by  Rietz  and  Smith  (1910)2  has 
also  been  used  in  studying  those  factors  which,  according  to  the  sur- 
vey method,  appear  to  affect  the  yield  to  the  greatest  extent.  The  survey 
method  of  studying  crop  production,  wholly  aside  from  the  agricultural 
methods  involved,  has  proved  to  be  a  most  valuable  means  of  determining 
the  actual  practice  thruout  the  State,  and  has  aided  in  correcting  many 
false  ideas  of  long  standing  concerning  cultural  methods  used  with  this 
crop. 

The  collection  of  data  was  begun  in  the  summer  of  1913  and  continued 
thru  the  summer  of  1914.  In  1913,  330  records  of  the  1912  potato  crop 
were  taken  from  as  many  potato  farms  on  Long  Island,  and  360  records 

1  Also  presented  to  the  Faculty  of  the  Graduate  School  of  Cornell  University,  February,  1919,  as  a  major 
thesis  in  partial  fulfillment  of  the  requirements  for  the  degree  of  doctor  of  philosophy. 
' 2  Dates  in  parenthesis  refer  to  Bibliography,  page  1274. 

1143 


1144 


V.  HAKDENBURG 


of  the  riame,  year  V:  crop  were  obtained  from  that  number,  of  farms  in 
northern  Steuberi  County.  In  1914,  300  records  were  similarly  taken  for 
the  1913  crop  in  Monroe  County,  and  300  in  Franklin  and  Clinton  Counties 
combined.  This  gives  a  total  of  1290  records  for  the  crops  of  1912  and 
1913.  Each  record  was  in  the  form  of  a  filled-out  survey  blank,  a 
sample  of  which  is  included  at  the  end  of  this  paper,  and  was  as  complete 
as  possible  in  the  details  listed.  Because  of  the  similarity  of  regional 
conditions  and  of  cultural  practices,  the  counties  surveyed  were  studied 


FlG.  125.   REGIONS  INCLUDED  IN  THE  POTATO 
SURVEY 


asjfour  distinct  sections,  as  follows:  (1)  Long  Island,  including  the  potato- 
growing  areas  of  Suffolk  and  Nassau  Counties;  (2)  Steuben  County;  (3) 
Monroe  County;  (4)  Franklin  and  Clinton  Counties.  The  location  of 
these  areas  is  shown  in  figure  125.  These  regions  were  selected,  not 
because  they  include  the  counties  of  highest  total  production,  but  because 
they  represent  typical  and  distinct  centers  of  potato  production  in  the 
State. 

The  importance  of  potato  production  in  a  region  is  probably  best 
indicated  by  figures  showing  the  percentage  of  total  crop  acres  devoted 
to  this  crop  and  the  average  potato  acreage  per  farm.  A  summary  of 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1145 

the  scope  of  the  survey  and  the  status  of  the  industry  during  the  years 
1912  and  1913  is  given  in  table  1.  Of  the  four  regions  surveyed,  the 
potato  crop  is  regarded  as  of  most  importance  on  Long  Island  and  of  least 
importance  in  Franklin  and  Clinton  Counties. 

TABLE  1.     SUMMARY  OF  THE  FOUR  REGIONS  SURVEYED 


Region 

Year 

Number 
of 
fecords 

Acreage 
surveyed 

Average 
size  of 
farm 
surveyed 
(acres) 

Per 
cent  of 
total 
acreage 
in 
potatoes, 
for 
farms 
sur- 
veyed 

Per 
cent  of 
crop 
acreage 
in 
potatoes, 
for 
farms 
sur- 
veyed 

Per 

,  cent  of 
crop" 
acreage 
in 
potatoes, 
for  the 
countv 
(1909 
census) 

Average 
potato 
acreage 
per 
farm 
sur- 
veyed 

Average 
yield 
per 
acre 
for 
farms 
sur- 
veved 
(bushels) 

Long    Island,    in- 
cluding parts  of 
Suffolk  and 
Nassau  Coun- 
ties 

1912 

330 

8,188  16 

65  0 

37 

44 

23  0 

24.8 

175.5 

Steuben  County.  . 
Monroe  County  .  . 
Franklin  and  Clin- 
ton Counties..  . 

1912 
1913 

1913 

360 
300 

300 

5,301.10 
3,728.25 

2,160.00 

145.8 
112.1 

169.5 

10 
11 

4 

18 
15 

10 

8.3 
8.0 

5.7 

14.7 
12.4 

7.2 

136.4 
126.2 

179.3 

THE  CROP  SURVEY  AS  A  METHOD  OF  RESEARCH 

From  its  inception  in  this  country,  agricultural  teaching  has  depended 
largely  on  textbooks,  collateral  references,  and  the  published  results  of 
experiments.  There  is  still  a  considerable  lack  of  practical  information 
which  can  be  supplied  only  by  protracted  experimentation  or  by  the 
study  of  large  numbers  of  survey  records  in  the  regions  concerned.  Fre- 
quently problems  arise  which  local  experiments  fail  to  solve  because  of 
the  impossibility  of  handling  the  work  on  a  sufficiently  extensive  scale. 
Large  numbers  of  records  might  very  often  be  the  means  of  discovering 
the  common  causal  factor  prevailing  thruout  a  region,  thus  furnishing  the 
solution  of  the  problem  or  at  least  a  working  basis  for  its  solution.  A 
typical  illustration  of  this  is  furnished  in  the  investigations  on  pecan 
rosette  by  McMurran  (1919).  Pathologists  had  previously  been  unable 
to  account  for  the  cause  or  to  recommend  measures  for  the  control  of 
this  disease,  which  was  so  prevalent  thruout  the  pecan  orchards  of  the 
Southern  States.  McMurran,  by  taking  records  of  many  orchards  in 
the  various  pecan  regions  of  the  South,  discovered  that  the  disease  was 
almost  entirely  absent  in  the  orchards  of  the  rich  river  bottom-  ands, 
and  from  this  observation  he  deduced  that  the  cause  of  the  disease  lay  in 
certain  soil  deficiencies. 

The  farm-crops  survey  aims  first  of  all  to  search  out  the  actual  facts 
concerned  in  the  production  of  a  given  crop  in  a  given  area.  This  informa- 
tion, obtained  in  sufficient  quantity,  may  then  be  regarded  as  statistics 


1146  EARLE  V.  HARDENBURG 

from  which  to  determine  the  most  beneficial  influences  and  practices. 
The  survey  idea  was  first  launched  in  New  York  by  Dr.  L.  H.  Bailey, 
under  whose  direction  horticultural  studies  were  made  thruout  the  State. 
In  1903  Professor  John  Craig  started  an  orchard  survey  campaign  in  west- 
ern New  York.  Such  of  these  surveys  as  were  completed  have  been 
published  as  Cornell  bulletins  (Warren,  1905,  a  and  b;  Cummings,  1909; 
Martin,  1911).  Under  the  direction  of  Dr.  G.  F.  Warren,  the  survey  idea 
was  extended  to  include  the  farm  as  a  whole,  with  the  result  that  whole 
farming  areas,  with  the  farm  as  a  unit,  have  been  studied  in  what  are 
called  farm-management  surveys.  The  results  of  such  studies  have  also 
been  published  as  Cornell  bulletins  (Warren  and  Livermore,  1911; 
Thompson,  1915).  Montgomery  (1913),  in  discussing  crop  surveys,  states 
that  their  primary  function  is  to  determine  how  to  grow  the  crop,  while 
farm-management  surveys  aim  to  determine  when  to  grow  the  crop. 
Warren  (1914)  attests  the  value  of  agricultural  surveys  by  saying  that  there 
are  many  kinds  of  agricultural  information  that  can  be  found  only  by 
survey  methods,  since  the  conditions  in  question  exist  only  on  the  farms. 
He  states  further  that  agricultural  knowledge,  to  be  of  most  value, 
should  be  the  result  of  both  survey  studies  and  experimental  tests. 

The  accuracy  of  survey  methods  depends  very  largely  on  such  factors 
as  the  personality  of  the  man  procuring  the  records,  the  manner  in  which 
questions  are  asked,  the  number  of  records  obtained  for  each  region  studied, 
the  unit  used  as  a  basis  in  the  study  of  a  factor,  accuracy  in  tabulation, 
and  the  final  interpretation  of  results.  The  more  extensive  the  record  to 
be  obtained,  the  greater  is  the  number  of  records  necessary  for  final 
accuracy.  The  principal  faults  in  much  of  the  survey  work  to  date  lie 
in  the  attempt  to  include  too  much  detail  and  in  the  use  of  too-  few  records. 
Warren  (1914)  is  of  the  opinion  that  ordinarily  1000  records  should  be 
used,  tho  500  may  be  enough  in  some  cases.  However,  the  necessity  of 
such  large  numbers  depends  somewhat  upon  the  scope  of  the  survey. 
By  the  law  of  averages,  large  numbers  tend  to  eliminate  individual  errors. 
Spillman  (1917)  has  said  that  the  accuracy  of  any  average  depends  on  three 
things:  first,  on  freedom  from  bias;  secondly,  on  the  number  of  items  from 
which  an  average  is  obtained;  and  thirdly,  on  the  accuracy  of  the  individual, 
items  averaged.  Considering  the  limitations  of  much  of  the  experimental 
evidence  to  date,  large  numbers  of  survey  records  are  undoubtedly  pro- 
ductive of  as  nearly  accurate  results  as  are  obtained  by  experimental 
work.  As .  emphasized  by  Warren  (1914),  the  region  surveyed  should  be 
an  agricultural,  not  a  political,  unit.  Furthermore,  the  records  should  be 
taken  only  during  a  normal  year  unless  records  are  to  be  obtained  for  con- 
secutive years.  Unfortunately  for  this  study,  the  year  1912  was  at  first 
drier  than  normal,  but  the  abundant  rain  which  fell  late  in  the  growing 
season  caused  some  blight  rot;  1913,  however,  was  a  more  nearly  normal 
year. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1147 

BIOMETRY  AS  APPLIED  TO  CROP-SURVEY  DATA 

Biometry  as  a  science  is  beginning  to  have  wide  application,  wherever 
sufficient  data  make  its  application  possible,  in  the  solution  of  problems 
involving  the  study  of  the  interrelation  of  factors  or  the  study  of  cause 
and  effect.  Until  the  present  time,  biometry  has  been  used  mainly  only 
in  the  study  of  inheritance  and  in  the  correlation  of  characters  in  large  popu- 
lations of  plants  and  animals.  Its  use  has  been  thus  limited  because  only  in 
such  studies  have  conditions  been  so  controlled  that  none  but  the  factor  or 
factors  under  observation  could  affect  the  results,  and  because  it  has  been 
possible  to  use  large  numbers  of  individuals  for  such  investigations. 
Biometry  should  have  a  place  in  the  study  of  crop-survey  data  wherever 
large  numbers  of  records  are  involved,  in  order  that  the  coefficient  of 
correlation  may  serve  as  a  check  on  the  conclusions  otherwise  drawn  and 
that  it  may  furnish,  thru  its  frequency  table,  a  description  of  the  prevailing 
practice  in  the  region  in  question. 

Tolley  (1917)  states  that  the  coefficient  of  net  correlation  affords  a 
good  means  of  determining  the  net  effect  of  each  of  several  factors  bearing 
on  a  result,  or  of  eliminating  the  effect  of  other  factors  when  it  is  desired 
to  find  the  true  relationship  between  any  two.  Applying  biometrical 
methods  to  farm-survey  data  on  fattening  baby  beef,  Tolley  has  shown 
how  the 'gross  apparent  correlation  between  any  two  or  more  factors  may 
be  substituted  in  a  derived  formula  and  the  net  correlation  of  any  two 
factors  thereby  deduced.  -r^'l 

A  biometrical  analysis  of  some  of  the  more  influential  factors  involved  in 
this  study  has"  been  made,  altho,  owing  to  the  relatively  large  numbers  of 
records  used  in  each  study,  only  the  gross  correlation  has  been  computed. 
Aside  from  the  actual  significance  of  the  coefficients  obtained,  much 
information  of  descriptive  value  relative  to  the  frequency  of  a  given 
practice  may  be  found  in  the  frequency  distribution  tables.  One  of 
the  chief  functions  of  biometry  is  description.  It  affords  a  means  of 
classifying  a  group  of  individuals  not  possible  by  any  other  means. 

THE  TAKING  OF  RECORDS 

Five  men  constituted  the  party  employed  in  the  taking  of  records  in 
1913.  This  made  it  possible  for  four  of  the  party  to  travel  thru  the 
potato  regions  in  pairs  while  the  fifth  man  copied  and  checked  each  day's 
records.  In  this  way,  any  discrepancies  in  the  records  could  be  checked 
up  by  a  return  visit  to  the  grower  or  by  discussion  within  the  party.  The 
data  on  the  1913  crop  were  taken  in  1914  by  two  ,men. 

As  previously  noted  (Spillman,  1917),  the  value  and  accuracy  of  survey 
data  depend  largely  on  freedom  from  bias.  This  may  well  apply  to  thje 
selection  of  farms  to  be  observed.  Therefore  it  was  decided  that  for  these 
surveys  the  only  limitation  in  the  selection  of  a  farm  was  to  be  in.  the 
acreage  of  the  crop  produced  the  previous  year.  This  limitation  was  set 


1148 


EARLE  V.  HARDENBURG 


at  a  minimum  of  5  acres,  tho  a  very  few  records  were  taken  on  farms 
having  a  production  area  of  only  4  acres.  The  reason  for  the  establish- 
ment of  this  minimum  limit  lies  in  the  assumption  that  growers  of  acreages 
smaller  than  5  are  probably  not  growing  potatoes  in  a  manner  comparable 
to  the  average  of  the  region.  The  data  on  cost  of  production,  tho  obtained 
at  the  same  time  and  indicated  on  the  survey  blank,  are  not  a  part  of  this 
study.  The  subject  of  cost  has  been  studied  by  Fox  (1919),  formerly  of 
the  Department  of  Farm  Management  at  Cornell  University. 

DESCRIPTION  OF  REGIONS  SURVEYED 

For  a  better  understanding  of  the  environmental  conditions  under 
which  the  potato  crop  was  produced,  a  brief  description  of  climate,  soil, 
topography,  elevation,  length  of  growing  season,  market  facilities,  type 
of  farming,  land  values,  and  status  of  potato  production,  is  given  for  each 
of  the  four  regions  surveyed.  Unfortunately,  of  the  regions  concerned, 
only  Monroe  and  Clinton  Counties  have  been  soil-surveyed  by  the  United 
States  Department  of  Agriculture.  More  detailed  knowledge  as  to  these 
environmental  influences  may  be  obtained  from  figures  126  to  129. 


FlG.  126.   ELEVATIONS  OF  THE  REGIONS  SURVEYED 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1149 


LONG    ISLAND 

Most  of  the  potato  crop  in  Suffolk  County  is  grown  east  of  Riverhead 
on  both  the  north  and  the  south  shores  of  Long  Island.  The  Long  Island 
Railroad  furnishes  the  transportation  facilities  for  practically  all  of  the 
surplus  crop  of  this  region.  Most  of  the  roads  are  improved  to  a  high 
degree.  Thus  the  time  required  for  shipments  to  reach  New  York  City 
need  not  be  over  one  day  and  no  delay  is  necessitated  by  transfers  to 
other  railroads. 


FlG.  127.      GROWING-SEASON   RAINFALL    (iN  INCHES) 
IN  REGIONS   SURVEYED 


Nearly  all  of  the  crop  in  Nassau  County  is  grown  north  of  a  line  drawn 
east  and  west  thru  the  central  part  of  the  county.  Most  of  the  surplus 
crop  of  this  county  is  transported  directly,  in  heavy  wagons  and  motor 
trucks,  to  the  Wallabout  and  Harlem  Markets  in  Brooklyn. 

The  greater  part  of  Long  Island  is  of  marine  deposit  formation,  the 
elevation  ranging  from  a  point  at  about  sea  level,  in  the  Hampton  section, 
to  an  altitude  of  nearly  300  feet  in  some  places  on  the  north  shore.  The 
average  elevation  of  the  potato  fields  surveyed  was  65.5  feet.  Due  to 
the  low  elevation  of  the  south  shore,  the  crop  is  exposed  to  heavy  sea  fogs 
which  make  conditions  favorable  to  the  development  of  late  blight.  The 


1150 


EARLE  V.  HARDENBURG 


topography  is  in  'general  fairly  level,  tho  the  slightly  rolling  lands  along 
the  north  shore  gradually  rise  until  they  merge  into  prominent  hills  along 
the  Sound. 

The  potato  sections  of  Long  Island  show  an  average  growing-season  ra'in- 
fall  of  from  16  to  20  inches,  which  is  somewhat  higher  than  that  of  most  of 
the  potato  sections  of  New  York.  Rainfall  seldom  limits  production  here. 
The  tempering  influence  of  the  Atlantic  Ocean  affords  a  growing  season  of 
approximately  200  days  between  killing  frosts,  which  is  greater  than  that 


FlG.  128.      LENGTH  OF  GROWING   SEASON  (iN  DAYS) 
IN  REGIONS   SURVEYED 


of  any  other  section  of  New  York.  The  growing  season  on  Long  Island 
is  fully  a  month  earlier  than  that  in  the  other  three  regions  under  dis- 
cussion. 

The  soil  of  most  of  the  potato-growing  areas  of  Long  Island  is  of  a  sandy 
texture,  topped  by  silty  loam  in  layers  of  varying  thickness.  This  is 
counter  to  a  rather  common  impression  that  the  Long  Island  crop  is  pro- 
duced in  sandy  soil.  The  greater  part  of  .the  central  section  of  the  island 
does  consist  of  sand,  and  this  supports  little  vegetation  aside  from  scrub 
oak  and  pine.  That  the  potatoes  are  grown  mainly  on  the  Sassafras 
series  of  soil  is  shown  in  figure  129. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1151 


1152  EARLE  V.  HARDENBURG 

The  importance  of  the  crop  on  Long  Island  is  shown  by  the  fact  that  no 
regular  system  of  crop  rotation  is  practiced,  potatoes  being  grown  for 
several  successive  years  on  the  same  land.  In  order  to  maintain  the 
humus  content,  cover  crops  of  rye  are  turned  under  each  spring.  The 
commonest  practice  is  two  to  four  years  of  potatoes,  the  land  being  cover- 
cropped  to  rye  over  winter.  Along  the  north  shore,  where  a  rotation 
is  sometimes  used,  wheat  seeded  to  clover  and  timothy  follows  potatoes, 
the  hay  being  grown  from  one  to  two  years  before  the  sod  is  plowed  for 
corn,  cabbage,  and  cauliflower.  Potatoes  then  follow  these  cultivated 


FlG.  130.      HARVESTING   IRISH    COBBLERS   IN    NASSAU    COUNTY   IN   JULY 
The  large  immature  vines  should  be  noted 

crops.     Wheat  and  hay  are  the  principal  rotation  crops  on  the  southern 
shore. 

Much  double-cropping  is  practiced  in  Nassau  County,  the  early  potatoes 
being  harvested  in  July  and  the  second  crop  in  late  August  and  early  Sep1 
tember.  Land  producing  a  first  crop  of  potatoes  is  commonly  planted  to 
turnips,  beets,  carrots,  or  other  root  crops,  or  is  set  to  cabbage  for  the  fall 
market.  Rye  is  used  here  also  as  a  cover  crop.  A  field  in  which  Cobblers 
were  harvested  one  day  and  turnips  were  planted  the  next  day,  is  shown 
in  figure  130. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES    1153 

Land  values  are  higher  on  Long  Island  than  in  the  other  potato  sections, 
partly  because  much  of  the  land  in  Nassau  County  is  held  for  real-estate 
purposes  and  partly  because  of  its  geographical  advantages  and  adapt- 
ability for  potato  production.  The  values  range  from  $100  an  acre  in 
Suffolk  County,  to  $1000  an  acre,  real-estate  value,  in  Nassau  County. 

The  average  size  of  the  farms  surveyed  was  65  acres,  of  which  37  per  cent- 
was  in  potatoes.  On  the  average,  44  per  cent  of  the  total  crop  acreage 
was  in  potatoes,  while  the  average  potato  acreage  per  farm  was  24.8. 
The  potato  crop  is  relatively  more  important  in  the  farming  system  here 
than  elsewhere  among  the  regions  surveyed. 

The  number  of  records  taken  on  Long  Island  was  330,  representing  a 
total  of  8188.16  acres  planted  to  potatoes  in  1912.  The  average  yield 
per  acre,  on  the  farms  surveyed,  was  175.5  bushels. 

STEUBEN    COUNTY 

The  area  of  most  intensive  production  in  Steuben  County  lies  in  its 
northeastern  part,  along  the  Cohocton  River  valley  and  in  the  hill  sections 
on  each  side.  The  Delaware,  Lackawanna  &  Western  and  the  Erie  Rail- 
road handle  the  potato  shipments.  Local  buyers  take  most  of  the  crop 
from  the  grower,  buying  it  either,  at  harvest  time  or  on  contract.  They 
store  it  in  temporary  warehouses  along  the  railroads  or  ship  it  direct. 
Because  of  the  unevenness  of  topography  and  the  heavy  nature  of  the 
soil  in  this  county,  the  highways  are  often  so  poor  that  the  movement  of 
the  crop  from  field  or  cellar  to  the  shipping  point  is  seriously  handicapped. 
For  this  reason,  most  of  the  crop  is  moved  at  the  times  when  the 
roads  are  in  the  best  condition.  Much  of  it  is  shipped  to  New  York 
and  Philadelphia,  but  the  variety  Spalding's  Rose  4  is  sent  to  Florida 
as  seed. 

The  elevation  of  the  surveyed  fields  ranged  from  1200  to  2100  feet,  the 
average  beingv!659.2  feet.  This  wide  range  in  elevation  has  considerable 
influence  on  the  development  of  the  potato  crop,  as  is  indicated  by  this 
study.  A  large  part  of  the  total  crop  is  produced  on  hillsides  of  varying 
slope,  the  incline  often  being  so  steep  as  to  limit  the  use  of  heavy  machinery; 
on  the  other  hand,  many  of  the  best  potato  fields  are  found  on  the  level 
table-lands  at  the  highest  elevations. 

Northern  Steuben  County  has  •  an  average  growing-season  rainfall  of 
from  16  to  18  inches,  which  is  sufficient  for  maximum  crops.  Because  of 
the  heavy  nature  of  the  soil,  years  of  abnormally  large  rainfall  often  cause 
much  loss  from  blight  rot.  The  growing  season  between  killing  frosts 
averages  150  days,  and  is  usually  sufficient  to  mature  the  crop.  Because 
of  better  air  drainage  and  cooler  average  temperatures,  the  crop  is  often 
later  and  the  yields  are  larger  on  the  farms  at  the  higher  elevations.  This 
was  not  the  case  in  1912,  however,  as  is  shown  later  in  the  discussion  of  the 
influence  of  elevation. 


1154  EARLE  V.  HARDENBURG 

Five  soil  series  are  principally  concerned  in  the  area  studied  in  Steuben 
County,  as  shown  by  figure  129.  Nearly  half  of  the  crop  of  1912  was  grown 
on  Lordstown  silt  loam,  which  gave  a  higher  average  yield  than  any  other 
series.  In  elevation  this  soil  series  is  next  to  the  Volusia  series,  which  is 
found  only  at  the  highest  elevations.  Tho  both  of  these  soil  series  are 
naturally  low  in  fertility,  the  highest  average  yield  was  obtained  on  the 
Lordstown  series,  while  the  lowest  average  yield  was  produced  on  the 
Volusia  series.  The  soils  on  the  hilltops  are  largely  derived  from  shale  and 
sandstone;  the  valley  soils,  altho  naturally  higher  in  fertility,  contain 
more  stone  and  gravel. 

Relatively  long  and  fixed  rotations  are  used  in  Steuben  County,  the  com- 
monest being  potatoes,  oats,  hay  two  years.  Frequently  the  sod  is  left 
until  long  past  its  profitable  stage  for  hay,  with  the  result  that  the  humus 
content  remaining  for  the  potato  crop  to  follow  is  seriously  depleted. 
Farms  on  which  the  sod  was  left  down  for  the  shortest  period  of  years 
showed  the  highest  yield,  and  vice  versa.  Sometimes  wheat  followed 
oats  in  the  rotation,  giving  two  successive  years  of  grain.  The  wheat  was 
used  as  the  nurse  crop.  These  farms  showed  a  higher  average  yield  of 
potatoes  than  did  the  farms  using  only  one  year  of  grain.  This  may  have 
been  due  to  the  additional  residual  fertilizer  left  from  the  second  year  of 
grain,  or  possibly  to  production  on  better  soil  than  is  ordinarily  devoted 
to  potatoes.  Buckwheat,  in  which  Steuben  County  ranks  second  according 
to  the  United  States  census  of  1909,  is  commonly  used  to  follow  old  sod 
land  that  is  being  broken  for  potatoes  or  to  break  virgin  land  recently 
cleared.  On  the  smaller  potato  farms,  corn  for  grain  or  silage  is  grown  in 
the  rotation  with  potatoes. 

Land  values  are  as  low  in  Steuben  County  as  anywhere  in  New  York, 
for  much  of  the  land  is  infertile  and  rough,  and  little  of  it  has  been  sold 
or  rented  in  recent  years.  The  estimated  values  ranged  from  $25  to  $80 
and  more  an  acre,  the  average  being  about  $50.  The  average  size  of  the 
farms  surveyed  was  145.8  acres,  10  per  cent  of  this  being  in  potatoes.  The 
per  cent  of  total  crop  acres  per  farm  in  potatoes  was  18'.  The  average 
yield  per  acre  on  the  360  farms  surveyed,  which  represented  a  total  of 
5301.1  acres  of  potatoes,  was  136.4  bushels. 

MONROE    COUNTY  ^ 

The  potato  section  of  Monroe  County  covers  most  of  the  region  east, 
west,  and  south  of  Rochester.  Potatoes  are  an  important  crop  on  most 
of  the  farms  south  of  the  fruit  belt  that  extends  across  the  northern  border 
of  the  county  abutting  on  Lake  Ontario.  Excellent  railroad  facilities  pro- 
vide transportation  for  the  marketing  of  the  crop,  loading  stations  being 
located  on  the  New  York  Central,  the  Lehigh  Valley,  the  Delaware, 
Lackawanna  &  Western,  the  Erie,  and  the  Buffalo,  Rochester,  &  Pittsburg 
Railroad. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1155 

Elevation  is  not  an  influential  factor  in  this  region,  since  its  variation 
is  only  between  400  and  1000  feet,  the  average  being  592.5  feet.  In  general 
the  topography  is  gently  rolling,  and  in  only  a  very  few  places  is  it  suffi- 
ciently uneven  to  affect  production  or  the  usual  cultural  practices. 

The  growing-season  rainfall  is  somewhat  less  than  that  of  the  other 
regions,  ranging  normally  from  14  to  16  inches.  However,  it  is  seldom 
insufficient  for  maximum  production.  Due  to  the  tempering  influence  of 
Lake  Ontario,  the  average  growing  season  is  165  days,  which  is  somewhat 
longer  than  that  of  the  other  regions  except  Long  Island. 

The  soils  on  which  the  potato  crop  is  produced  are  principally  of  the 
Dunkirk  and  Ontario  series,  as  shown  in  figure  129.  Altho  both  of  these 
soils  are  naturally  fairly  fertile,  a  study  of  comparative  yields  shows  that, 
other  things  being  equal,  the  Dunkirk  soils  gave  the  higher  production. 
The  soil  map  of  Monroe  County  shows  an  especially  wide  range  in  soil 
types  within  each  of  these  series. 

The  cropping  system  of  this  region  is  usually  a  four-years  rotation  of 
potatoes  and  grain  or  another  crop,  oats,  wheat,  hay.  Corn  is  most 
commonly  chosen  as  the  additional  cultivated  crop  to  be  raised  with 
potatoes,  tho  beans  and  cabbage  are  sometimes  used.  The  value  of  potato 
land  ranged  from  $50  to  $250  an  acre,  the  average  acre  value  being  $150. 
The  farms  surveyed  averaged  112.07  acres  in  size,  11  per  cent  of  the  total 
acreage  being  in  potatoes;  and  the  importance  of  the  crop  is  emphasized 
by  the  fact  that  15  per  cent  of  the  crop  acreage  is  in  potatoes.  The  average 
yield  per  acre  of  the  1913  crop,  for  the  3728.25  acres  of  potatoes  on  the 
300  farms,  was  126.2  bushels. 

FRANKLIN   AND    CLINTON    COUNTIES 

The  areas  of  production  in  Franklin  and  Clinton  Counties  are  two:  one 
consists  of  a  broad,  level  stretch  of  fertile  valley  land  along  the  St.  Law- 
rence River,  extending  across  the  northern  end  of  Franklin  County  and 
over  into  Clinton  County;  the  other  consists  of  hill  and  valley  farms 
on  each  side  of  the  Saranac  River,  in  central  Clinton  County.  In  both  these 
areas  the  potato  lands  extend  back  into  the  foothills  of  the  Adirondack 
Mountains.  Most  of  the  production  centers  in  Franklin  County  are  located 
along  the  Rutland  Railroad,  while  the  Delaware  and  Hudson  Railroad 
handles  most  of  the  crop  of  Clinton'  County.  The  greater  part  of  the  sur- 
plus is  marketed  in  the  eastern  seaboard  markets  after  the  early  crops  of 
Long  Island,  New  Jersey,  and  the  South  have  been  sold.  A  thriving 
trade  in  seed  potatoes  has  been  developed  with  Long  Island,  New  Jersey, 
and  southern  points. 

Being  in  close  proximity  to  the  Adirondack  Mountains,  this  region  has 
a  wide  range  in  elevation.  It  varies  from  300  to  1850  feet,  the  average 
for  the  farms  surveyed  being  1038.2  feet.  The  excellent  yields  obtained 
at  the  higher  altitudes  are  due  largely  to  the  cool  climate  there  afforded. 


1156  EAKLE  V.  HARDENBURG 

In  spite  of  the  range  in  elevation,  very  little  of  the  crop  is  produced  on 
anything  but  level  land.  The  farms  along  the  St.  Lawrence  River  valley 
are  generally  level  or  gently  sloping  toward  the  river,  and  most  of  the  crop 
in  Clinton  County  is  also  grown  on  fairly  level  fields,  either  in  the  Saranac 
River  valley  or  on  top  of  the  foothills  of  the  Adirondack^. 

Due  to  the  northerly  latitude  of  this  region  the  growing  season  is  rela- 
tively short,  the  average  period  between  killing  frosts  being  150  days. 
Elevation  and  latitude  are  jointly  contributing  factors  for  an  ideal  potato 
climate  conducive  to  late  maturity  of  the  crop.  As  a  rule  the  growth  is 
stopped  by  frost,  resulting  in  a  crop  more  or  less  immature  at  harvest 
time.  This  gives  a  product  of  excellent  seed  value  and  keeping  qualities. 
The  growing-season  rainfall  averages  from  14  to  18  inches,  the  mountain 
areas  receiving  the  greater  precipitation.  The  rainfall  is  uniform  thruout 
the  growing  season,  each  month  averaging  3  or  more  inches. 

Most  of  the  soils  of  this  region  are  a  fine  sandy  loam  and  are  included 
in  the  Ontario,  Calqma,  and  Terrace  soil  series.  The  Ontario  series  com- 
prises the  area  along  the  St.  Lawrence  River,  and  the  Caloma  and  Terrace 
soils  comprise  most  of  the  area  in  central  Clinton  County  (fig.  129).  The 
Ontario  series  is  largely  of  sedimentary  origin  and  its  fertility  is  rather 
higher  than  the  average;  while  the  Caloma  and  Terrace  soils  are  mainly 
of  glacial  drift  formation  and  are  of  only  mediocre  fertility. 

The  commonest  system  of  cropping  is  a  five-years  rotation  of  potatoes 
and  corn,  oats,  hay  three  years.  The  corn  is  used  mainly  for  silage. 
Hops  have  been  regarded  as  a  relatively  important  cultivated  crop  in  the 
Franklin  County  area  until  recently,  when  low  prices,  disease,  and  com- 
petition with  the  western  crop  caused  a  decided  decrease  in  acreage.  At 
present,  potatoes  are  the  chief  source  of  cash  income  in  this  district.  Land 
values  here  are  similar  to  those  in  Steuben  County,  the  range  being  from 
$10  to  $100  an  acre,  with  the  average  at  about  $50. 

The  average  size  of  the  farms  surveyed  was  169.5  acres.  Only  4  per 
cent  of  the  total  acreage,  and  10  per  cent  of  the  crop  acreage,  was  in 
potatoes.  The  average  yield  per  acre  on  the  300  farms  surveyed,  repre- 
senting 2160  acres,  was  179.3  bushels. 

METHOD  OF  STUDYING  SURVEY  DATA 

As  previously  pointed  out,  one  of  the  handicaps  in  any  effort  to  de- 
termine, by  an  analysis  of  survey  data,  the  absolute  influence  of  a  single 
factor  on  yield,  lies  in  the  difficulty  of  separating  the  influence  of  other 
factors  from  that  of  the  one  in  question.  This  is  a  necessary  step,  how- 
ever, in  insuring  accuracy  and  a  correct  interpretation  of  results.  A 
preliminary  study  of  factors  influencing  potato  yield  in  Steuben  County 
in  1912  (Hardenburg,  1915  b)  indicated  that  the  most  important  factors 
were  the  amount  of  seed  used  per  acre,  the  value  of  manure  and  fertilizer 
employed  per  acre,  and  the  frequency  of  bordeaux  spraying.  The  results 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1157 

of  the  present  study  have  borne  out  that  conclusion.  Therefore,  in  con- 
sidering the  influence  of  a  given  factor  on  yield,  an  effort  has  been  made 
to  eliminate  as  far  as  possible,  or  at  least  to  give  due  credit  to,  other  con- 
tributing factors. 

Since  the  study  of  each  region  concerns  but  a  single  year,  too  definite 
conclusions  must  not  be  drawn  in  interpreting  the  data  presented.  De- 
pending upon  the  normality  of  the  season  in  which  the  crop  was  grown, 
the  degree  of  influence  of  a  given  factor  may  or  may  not  be  maintained 
under  average  conditions.  Tho  cultural  practices  are  not  usually  varied 
radically  from  one  year  to  another,  differences  in  the  length  of  the  grow- 
ing season,  in  the  average  growing-season  temperature,  and  in  rainfall, 
tend  to  affect  the  influence  of  those  practices.  Therefore  it  will  not  be 
possible  to  answer,  in  any  appreciable  degree,  many  of  the  questions 
that  will  be  raised.  The  consideration  of  experimental  results  is  there- 
fore of  value  in  furnishing  background  for  the  study  of  each  factor.  As 
stated  by  Warren  (1914),  there  are  questions  that  can  be  answered  only 
by  a  study  of  the  results  obtained  on  farms,  and  other  questions  that  can 
be  answered  only  by  the  results  of  experiments. 

Little  attempt  has  been  made  to  discuss  any  potato  literature  except 
that  pertaining  to  seed,  fertilizers,  and  planting,  these  being  obviously 
the  most  influential  factors  under  the  grower's  control.  In  reviewing  the 
literature,  one  is  impressed  by  the  large  quantity  available  and  by  the 
meagerness  and  unreliability  of  the  data  given  to  substantiate  the  state- 
ments. 

THE  STUDY  OF  FACTORS 
CLIMATE 

A  brief  review  of  climatic  conditions  in  each  of  the  surveyed  areas  has 
been  given,  not  because  of  any  definite  influence  on  the  crop  under  con- 
sideration, but  to  make  clearer  the  normal  conditions  to  which  the  crop 
is  subject.  Facilities  for  taking  weather  data  in  each  of  these  regions 
are  not  yet  sufficient  to  allow  of  any  attempt  at  the  correlation  of  rainfall 
and  temperature  with  yield  for  a  given  year. 

In  general,  the  average  growing-season  temperature  to  which  the  crop 
is  subject  has  a  marked  influence  on-  the  vitality  of  that  crop  as  used  for 
seed.  Briefly,  high  temperatures  tend  to  produce  devitalization.  Long 
Island  growers  obtain  average  yields  ranging  from  150  to  250  bushels  per 
acre  from  new  Maine  seed,  but  the  use  of  the  same  stock  for  seed  a  second 
year  results  in  greatly  inferior  yields,  as  is  indicated  in  figure  131.  The 
same  principle  is  demonstrated  in  the  rather  common  practice  of  introduc- 
ing seed  from  northerly  latitudes,  a  practice  which  is  justified  on  the  basis 
of  better  yields,  as  is  shown  in  the  tests  cited  under  the  caption  Source 
of  seed. 


1158 


EARLE  V.  HARDENBURG 


FlQ.    131.       GROWTH    VARIATION    BETWEEN    NEW    AND    ONE-YEAR-OLD    MAINE    SEED    STOCK    ON 

LONG   ISLAND 
The  photograph  shows  also  the  characteristic  topography  of  potato  lands  in  Suffolk  County 

Valuable  studies  of  the  influence  of  weather  on  the  yield  of  potatoes 
in  Ohio  for  a  period  of  fifty-five  years  have  been  made  by  Smith  (1915), 
and  a  similar  study  for  a  period  of  twenty-six  years  has  been  made  in 
New  York  by  Fox  (1916).  The  relationship  of  both  growing-season 
rainfall  and  temperature,  in  both  States,  is  expressed  in  terms  of  the 
coefficient  of  correlation  (r).  A  comparison  of  these  coefficients  shows 
that  July  is  by  far  the  most  critical  month  with  respect  to  these  factors, 
in  both  Ohio  and  New  York.  The  coefficient  of  correlation  between  tem- 
perature and  yield  is  in  most  cases  negative  for  both  States,  indicating 
that  yield  is  inversely  proportional  to  increase  in  temperature.  So  far 
as  rainfall  is  concerned,  the  correlation  for  Ohio  is  positive  and  fairly 
large,  indicating  that  rainfall  is  ordinarily  a  limiting  factor  in  yield.  The 
correlation  of  rainfall  and  yield  in  New  York,  on  the  other  hand,  is  negative, 
showing  that  years  of  high  rainfall  are  years  of  low  yield.  The  average 
growing-season  rainfall  for  the  potato  sections  of  New  York,  previously 
given  as  ranging  from  14  to  20  inches,  is  evidently  sufficient  for  this  crop. 
The  negative  coefficient  of  correlation  is  probably  a  reflection  of  the  fact 
that  years  of  highest  rainfall  in  New  York  have  been  years  of  severe  loss 
from  blight  rot. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1159 


ELEVATION 

Elevation  as  a  factor  influencing  production  has  been  determined  from 
the  figures  shown  on  the  topographic  sheets  of  the  surveyed  areas  pub- 
lished by  the  United  States  Geological  Survey.  As  far  as  possible,  the 
location  of  the  potato  fields  for  which  data  were  taken  was  indicated  on 
these  topographic  sheets  at  the  time  of  taking  the  data.  The  chief 
difficulty  in  determining  the  absolute  influence  of  elevation  lies  in  the 
fact  that  increase  or  decrease  in  elevation  is  usually  accompanied  by  a 
difference  in  soil  type.  A  study  of  elevation,  therefore,  really  involved 
also  the  consideration  of  both  climate  and  soil.  The  writer  is  not  aware 
that  any  test  has  ever  been  made  in  which  either  one  or  the  other  of  these 
factors  was  studied  with  the  other  factor  eliminated. 

Progressive  increases  in  altitude  and  in  latitude  are  similar  in  that  each 
is  accompanied  by  a  reduction  in  temperature.  The  United  States 
Weather  Bureau,  in  computing  temperature  equivalents,  makes  use  of  the 
principle  that  every  300  feet  rise  in  altitude  is  accompanied  by  a  reduc- 
tion in  temperature  of  one  Fahrenheit  degree. 

Influence  of  elevation  on  Long  Island 

Elevation  cannot  be  considered  a  potent  factor  in  the  Long  Island  area, 
for  its  highest  point  does  not  greatly  exceed  200  feet.  Many  farms  along 
the  south  shore  of  Suffolk  County  are  below  sea  level,  the  sand  dunes 
alone  keeping  out  the  sea.  A  typical  Long  Island  potato  field  is  shown 
in  figure  131.  The  relation  of  elevation  to  yield  in  1912  is  shown  in 
table  2: 

TABLE  2.    RELATION  OF  ELEVATION  TO  YIELD  ON  327  LONG  ISLAND  FARMS  IN  1912 


Elevation 
(feet) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels)  i 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 
per  acre 

Average 
elevation 
(feet) 

1-50 

157 

178.3 

12.9 

$35.31 

26.4 

50  -  100 

87 

157.5 

12.0 

27.71 

64.8 

100-150 

53 

184.3 

12.4 

32.20 

117.2 

150  -  200 

22 

188.8 

12.2 

33.01 

167.7 

200  and  over 

8 

196.3 

13.4 

31.65 

218.1 

Total 

327 

. 

Average  .  .  . 

175.3 

12.5 

$32.39 

65.5 

1160 


EARLE  V.  HARDENBURG 


Altho  there  is  no  proof  in  table  2  that  the  yield  increases  with  an  increase 
in  elevation,  there  is  a  slight  indication  that  this  may  be  true.  The  farms 
located  at  50  to  100  feet  elevation  had  a  lower  yield  than  those  at  the 
lowest  elevation,  partly  because  they  received  less  seed  and  fertilizer 
than  any  other  group.  Furthermore,  the  farms  at  the  lowest  elevation 
received  slightly  more  than  the  average  amount  of  seed  and  fertilizer  per 
acre.  It  is  improbable,  however,  that  the  wide  difference  in  yield  between 
the  two  groups  at  the  lowest  elevations  was  due  entirely  to  differences 
in  amount  of  seed  and  fertilizer.  There  may  have  been  some  basic  reason 
why  the  87  growers  at  the  50-to-100-feet  elevation  used  the  least  seed 
and  the  least  fertilizer,  which  would  account  in  part  for  the  lower  yield. 
No  such  reason  is  apparent,  however,  from  the  data  at  hand. 

Influence  of  elevation  in  Steuben  County 

The  average  elevation  of  the  farms  visited  in  Steuben  County  is  greater 
than  in  any  other  of  the  regions  concerned  in  this  survey,  it  being  1659.2 
feet.  The  elevation  varies  from  1200  to  2100  feet,  a  range  of  900  feet, 
and  within  this  range  there  is  a  considerable  variation  in  the  soil  types, 
as  is  shown  later  in  table  13  (page  1770).  A  summary  of  the  average 
yields  obtained  at  various  elevations  is  given  in  table  3 : 

TABLE  3.      RELATION  OF  ELEVATION  TO  YIELD  ON  355  STEUBEN  COUNTY  FARMS  IN  1912 


Elevation 

(feet) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
unharvested 
yield 
per  acre 
(bushels) 

Average 
elevation 
(feet) 

1200-1300.  . 

9 

148.8 

24.6 

1,243.6 

1300-1400  

36 

156.6 

13.1 

1,336.0 

1400  -  1500 

39 

129  7 

20  5 

1,426  2 

1500-1600 

46 

136  4 

20  0 

1,530  4 

1600  -  1700 

46 

133  9 

24  1 

1  ,  630  .  2 

1700-1800   . 

63 

131  6 

29  0 

1,732.1 

1800-1900   . 

61 

138  3 

30  7 

1,829.7 

1900  -  2000  .... 

34 

134  6 

27.9 

1,920.4 

2000-2100  

21 

124  7 

17.0 

2,033.4 

Total 

355 

Average 

136  4 

24  2 

1  ,  659  .  2 

A  general  tendency  for  yields  to  decrease  as  elevation  increases  is 
ndicated  by  table  3.  This  is  counter  to  the  expected  influence  of  altitude, 
and  may  be  explained  by  the  fact  that  the  soil  at  the  higher  altitudes  of 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1161 


this  region  is  heavier  and  of  lower  natural  fertility.  Further  evidence 
of  this  condition  is  found  in  the  figures  showing  a  greater  percentage  of 
unharvested  yield  due  to  blight  rot,  which  is  so  common  in  these  heavier 
soils,  at  the  higher  elevations. 

The  Green  Mountain,  or  white-sprout,  type  of  potato  withstands  less 
heat  than  does  the  Rural,  or  blue-sprout,  type.  Where  the  growing- 
season  temperature  is  relatively  cool,  as  in  Franklin  and  Clinton  Counties 
and  on  Long  Island,  the  white-sprout  type  is  therefore  more  common. 
In  Steuben  County,  of  94  farms  growing  the  white-sprout  potatoes,  61 
per  cent  were  located  above  1660  feet  elevation  and  only  39  per  cent  were 
located  below  this  level.  Of  239  farms  growing  the  blue-sprout  type, 
50  per  cent  were  above  and  50  per  cent  were  below  1660  feet  elevation. 
There  is  some  tendency,  therefore,  to  grow  more  of  the  white-sprout  type 
at  the  cooler  altitudes. 

Influence  of  elevation  in  Monroe  County 

The  range  of  elevation  in  Monroe  County  is  between  400  and  slightly  over 
800  feet.  Little  opportunity  is  therefore  afforded  to  study  the  influence 
of  this  factor  in  this  region.  The  figures  in  table  4,  interpreted  in  the  light 
of  average  seed  and  fertilizer  used,  show  that  elevation  has  some  tendency 
to  increase  yield. 

TABLE  4.      RELATION  OF  ELEVATION  TO  YIELD  ON  296  MONROE  COUNTY  FARMS  IN  1913 


Elevation 

(feet) 

Number  of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

400-500   . 

30 

130  5 

12  6 

$14  03 

500-600   . 

107 

122  8- 

12  5 

11  20 

600-700.  . 

129 

116  0 

12  4 

10  86 

700  -  800  .. 

23 

•165  2 

12  5 

11  56 

800  and  over 

7 

225  4 

14  7 

11  39 

Total   .... 

296 

Average  .  . 

127  1 

12  5 

$11  34 

Influence  of  elevation  in  Franklin  and  Clinton  Counties 

A  variation  of  over  1500  feet  elevation  in  the  farms  in  Franklin  and 
Clinton  Counties  affords  excellent  opportunity  for  the  study  of  the  influence 
of  elevation  on  yield.  The  summary  given  in  table  5  shows  a  rather  marked 


1162 


EARLE  V.  HARDENBURG 


TABLE  5.      RELATION  OF  ELEVATION  TO  YIELD  ON  290  FKANKLIN  AND  CLINTON  COUNTY 

FARMS  IN  1913 


Elevation 
.     (feet) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Average 
elevation 

(feet) 

300-  600 

33 

154  8 

11  6 

$12  90 

437  7 

600-800 

19 

154  9 

10  9 

11  12 

697  1 

800  -  1000  . 

31 

185  1 

11  5 

13  09 

895  5 

1000  -  1200  ... 

47 

184  0 

12  1 

13  10 

1  094  4 

1200-1400  

101 

179  1 

12  2 

12  72 

1,296  9 

1400-1600  

42 

191  0 

12  5 

13  22 

1,468  6 

1600-1850  

17 

193  4 

11  8 

14  13 

1,709  7 

Total  

290 

Average 

177  3 

11  9 

$12  91 

1  038  2 

influence  of  this  factor.  With  the  amounts  of  seed  and  the  value  of  manure 
and  fertilizer  used  approximately  equal,  the  best  yields  were  produced  at 
the  higher  mountain  elevations. 

Since  the  increase  in  elevation  for  this  'region  is  accompanied  by  a  con- 
siderable variation  in  soil  type,  a  part  of  the  increase  in  yield  at  the  higher 
levels  may  be  due  to  the  latter  factor.  However,  since  Franklin  County 
has  not  been  soil-surveyed,  it  is  impossible  here  to  measure  accurately 
the  influence  of  the  soil.  Very  little  difference  in  soil  type  was  evident 
between  the  Dover  fine  sandy  loam  of  the  lower  elevations  and  the 
Caloma  fine  sandy  loam  of  the  higher  elevations  in  Clinton  County. 

CROP  ROTATION 

The  benefits  of  crop  rotation  to  a  heavy-feeding  cultivated  crop  such  as 
potatoes  have  long  been  recognized.  The  crop  survey  as  a  means  of  com- 
paring various  rotations  in  a  given  region,  however,  has  very  limited  possi- 
bilities, for  in  the  older  farming  regions  the  same  general  type  of  rotation 
is  followed  thruout.  Very  few  tests  have  thus  far  been  made  by  the  experi- 
ment stations  to  determine  the  most  suitable  place  in  the  rotation  and  the 
best  length  of  rotation  for  potatoes  in  a  given  region.  Probably  the  most 
valuable  work  has  been  done  by  Hartwell  and  Damon  (1916)  in  their 
twenty-years  comparison  of  different  rotations  of  corn,  potatoes,  rye,  and 
grass,  at  the  Rhode  Island  Station.  The  principal  feature  of  this  work 
lies  in 'a  comparison  of  four-,  five-,  and  six-years  rotations  of  potatoes, 
jye  and  rowen,  grass,  corn,  the  grass  being  left  down  for  from  one  to  three 
years.  No  stable  manure  was  used,  but  complete  commercial  fertilizers 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1163 


were  added  to  the  sod  each  year.  In  the  matter  of  fertilizers,  Hartwell 
and  Damon's  experiment  is  not  comparable  to  farm  practice  in  New  York, 
where  little  or  no  commercial  fertilizer  is  ever  used,  stable  manure  being 
generally  applied,  instead,  as  a  top  dressing,  during  the  last  year  of  sod 
or  perhaps  just  before  plowing  for  corn  or  potatoes.  The  average  yields 
per  acre  of  potatoes  obtained  by  Hartwell  and  Damon,  in  the  rotations 
including  grass  for  one,  two,  and  three  years,  were  200,  199,  and  223 
bushels,  respectively.  It  appears  that  their  commercial-fertilizer  treat- 
ments were  sufficient  to  maintain  a  maximum  condition  of  sod  thruout  the 
three  years. 

A  test  on  the  influence  of  various  fertilizers  on  potatoes,  conducted  at 
the  Rothamsted  station,  is  reported  by  Hall  (1905).  In  this  test  the  crop 
was  grown  for  twenty-six  consecutive  years  on  the  same  land,  and  under 
each  treatment  the  yields  declined  during  the  later  as  compared  to  the 
earlier  years  of  the  test.  Long  Island  is  the  only  section  in  New  York 
in  which  the  crop  is  grown  without  rotation,  and  it  is  only  the  in- 
creased use  of  fertilizers  that  has  maintained  yields  there.  Not  only  is  it 
difficult  to  get  sufficient  stable  manure  for  the  potato  crop  on  Long  Island, 
but  many  growers  do  not  find  it  economical  to  haul  fertilizer  in  this  form  so 
great  a  distance  as  would  often  be  necessary.  Consequently,  each  year 
more  than  a  third  of  the  growers  sow  a  cover  crop  of  rye  after  potatoes. 
Some  use  the  cover  crop  every  year,  while  others  use  it  only  every  second 
or  third  year,  and  some  not  at  all.  In  the  consideration  of  the  influence  of 
cover  crops  on  yield,  only  those  fields  are  included  on  which  a  cover  crop 
was  grown  in  the  fall  and  winter  preceding  the  potato  crop.  In  table  6 
the  average  yields  that  are  obtained  directly  after  cover  crops,  are  com- 
pared with  those  obtained  when  no  previous  cover  crop  had  been  used. 

TABLE  6.     RELATION  OF  COVER  CROP  TO  YIELD  ON  313  LONG  ISLAND  FARMS  IN  1912 


Treatment 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average  value 
of  manure  and 
fertilizer  per 
acre 

Cover  crop 

'    131 

174  1 

12  6 

$32  61 

No  cover  crop 

182 

177  3 

12  5 

32  25 

Total     . 

313 

Average 

175  5 

12  5 

$32  40 

The  figures  given  in  table  6  should  not  be  construed  to  mean  that  cover 
crops  are  not  beneficial  to  the  potato  crop  on  Long  Island,  because  the 


1164 


EAELE  V.  HARDENBURG 


yields  obtained  in  the  group  listed  as  not  using  a  cover  crop  may  have  been 
produced  on  farms  which  used  a  cover  crop  two  or  three  years  previously 
or  on  farms  whose  soil  was  naturally  higher  in  organic  content.  Granting 
vthis,  the  data  on  cover  crops  for  Long  Island  are  not  sufficient  to  indicate 
either  advantage  or  disadvantage  accruing  from  its  use.  It  is  true  that 
in  1912  growers  who  had  not  sown  a  cover  crop  the  previous  fall  did  not 
attempt  to  supplement  the  soil  fertility  by  using  more  fertilizer.  This 
in  itself  may  indicate  that,  in  the  main,  only  those  growers  who  actually 
needed  the  cover  crop  to  maintain  yields  were  the  ones  who  used  it. 

The  rotations  followed  in  Steuben  County,  consisting  usually  of  potatoes, 
grain,  and  hay,  vary  principally  in  the  number  of  successive  years  that 
the  hay  and  the  grain  are  left  on  the  same  ground.  Commercial  fertilizer 
is  applied  lightly  at  the  time  of  planting  potatoes,  and,  altho  what  stable 
manure  is  available  is  put  on  the  sod  to  be  plowed  for  potatoes,  there 
is  seldom  enough  to  cover  the  entire  potato  acreage.  The  yields  of  hay  are 
largely  dependent  on  the  residual  fertilizer  left  from  that  applied  directly  to 
the  grain  crops.  Thus  in  the  longer  rotations,  in  which  sod  is  left  down  for 
three  or  more  years,  only  a  poor  supply  of  root  and  stubble  residue  is  left 
to  supply  humus  to  the  potato  crop.  A  comparison  of  the  influence  on 
the  yield  of  various  types  of  rotations  in  this  region  is  shown  in  table  7: 

TABLE  7.      RELATION  OF  ROTATION  TO  YIELD  ON  240  STEUBEN  COUNTY  FARMS  IN  1912 


Manure  or  fertilizer  on 

Manure  or  fertilizer  on 

No  manure  nor  fertilizer 

part  of  acreage 

entire  acreage 

used 

Rotation 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount 
of  seed 
used 
per 
acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acrej 
(bushels) 

Average 
cost  of 
manure 
and 
ferti- 
lizer 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount 
of  seed 
used 
per 
acre 
(bushels) 

Potatoes,  grain,  hay.  . 

13 

177.0 

10.9 

8 

189.1 

$10.51 

1 

150.0 

7.5 

Potatoes,  grain,  hay, 

hay  

117 

134.9 

10.3 

58 

150.1 

13.98 

7 

106.2 

9.6 

Potatoes,  grain,  hay, 

hay,  hay  

62 

122.7 

10.0 

26 

135.0 

11.95 

3 

103.6 

10.5 

Potatoes,  grain,  grain, 

hay,  hay  

25 

150.1 

9.2 

12 

160.9 

13.34 

Potatoes,  grain,  grain, 

hay,  hay,  hay  

11 

143.0 

8.8 

5 

160.2 

20.34 

1 

50.0 

8.8 

Eliminating  the  factors  of  seed  and  fertilizer  as  given  in  table  7,  the  yield 
consistently  decreased  with  each  successive  year  that  the  sod  remained  in 
rotation.  This  shows  the  tendency  of  the  seeding  to  become  thinner  and  of 
less  value  as  a  source  of  humus  for  the  potato  crop,  the  older  it  becomes. 
The  figures  for  the  last  two  rotations  in  the  table  —  which  differ  from  the 
first  three  in  that  they  contain  two  years  of  grain  instead  of  one,  and  from 


A  STUDY  OF  FACTORS  INFLUENCING,  THE  YIELD  OF  POTATOES     1165 


each  other  only  in  the  number  of  years  of  successive  hay  crops  —  show 
a  higher  average  yield  of  potatoes  with  them  than  with  the  first  three. 
This  may  be  due  to  the  additional  residual  fertilizer  left  from  that  applied  to 
the  extra  year  of  grain,  or  to  the  factor  of  naturally  better  soil  as  indicated 
by  the  tendency  to  produce  more  grain. 

The  type  of  rotation  commonest  in  each  region  is  indicated  by  the  figures 
in  table  8  on  the  percentage  of  total  crop  acres  occupied  by  each  crop 
listed.  No  fixed  rotation  is  indicated,  for  Long  Island,  where  potatoes  are 
grown  for  a  varying  number  of  successive  years  on  the  same  land.  The 

TABLE  8.     RELATIVE  IMPORTANCE  OF  CROPS  ON  FARMS  SURVEYED 


Crop 

Per  cent  of  crop  acres 

Long 
Island 

Steuben 
County 

Monroe 
County 

Franklin 
and 
Clinton 
Counties 

.  Average 

Hay  
Potatoes  
Oats  
Corn  for  grain  
Wheat  ,. 
Orchard  
Rye  
Corn  for  silage  
Cabbage  
Sweet  corn  
Beans  

12 
43 
2 
15 
5 
0 
1 
1 
4 
5 
1 
0 
5 
0 
4 
2 
0 
0 
0 
0 
0 

42 
18 
21 
1 
3 
1 
4 
0 
0 
0 
0 
4 
0 
2 
0 
0 
1 
1 
1 
1 
0 

24 
15 
17 
6 
14 
8 
4 
2 
3 
1 
4 
0 
0 
1 
0 
0 
0 

1 

0 
0 
0 

59 
10 
19 
1 
0 
2 
1 
4 
0 
0 
0 
1 
0 

1 

0 
0 

1 

0 
0 
0 

1 

34.25 
21.50 
14.75 
5.75 
5.50 
2.75 
2.50 
1.75 
1.75 
1.50 
.25 
.25 
.25 
.00 
.00 
0.50 
0.50 
0.50 
0.25 
0.25 
0.25 

Buckwheat  

Cauliflower  

Barley  
Garden  truck  

Brussels  sprouts  
Corn  for  fodder  
Alfalfa  

Peas  

Oats  and  barley  
Sugar  bush  •  

figures  for  Steuben  County  indicate  a  rotation  of  potatoes,  oats,  hay 
two  years;  those  for,  Monroe  County,  a  rotation  of  potatoes  with  corn  or 
beans  or  cabbage,  oats,  wheat,  hay  one  to  two  years ;  and  those  for  Franklin 
and  Clinton  Counties,  a  rotation  of  potatoes  with  corn,  oats,  hay  three 
years. 

A  review  of  the  experimental  literature  on  the  influence  of  crop  rotation 
in  potato  production  shows  a  striking  preference  for  either  grass,  or  a 


1166  EARLE  V.  HARDENBURG 

legume  productive  of  considerable  vegetative  growth,  as  a  crop  to  precede 
potatoes.  This  is  evidence  of  the  efficient  use  which  the  potato  crop  is 
able  to  make  of  this  form  of  organic  material.  Such  legumes  as  cowpeas, 
soybeans,  and  crimson  clover  commonly  precede  potatoes  in  the  Southern 
and  the  South  Atlantic  States,  while  timothy,  in  combination  with  red  or 
alsike  clover,  is  used  generally  thruout  the  principal  potato  States.  Alfalfa 
is  considered  the  ideal  legume  to  precede  potatoes  in  the  alfalfa  belt  of  the 
West.  The  root  and  stubble  residue  from  these  crops  not  only  contributes 
to  the  food  requirements  of  the  potato,  but  also  improves  the  aeration, 
the  temperature,  and  the  moisture-holding  ability  of  the  soil. 

Generally  speaking,  the  rotations  of  the  three  regions  aside  from  Long 
Island  are  long  enough  not  to  serve  as  factors  limiting  yield  except  as  the 
type  of  rotation  may  affect  fertilizing  practices.  Inasmuch  as  the  avail- 
able stable  manure  is  not  usually  applied  for  the  benefit  of  the  hay  crops, 
and  the  residual  organic  fertility  is  not  thereby  maintained  or  improved, 
the  sod  residue  commonly  turned  under  before  potato  planting  is  usually 
less  Valuable  after  a  three-years  stand  than  after  a  stand  of  shorter 
duration. 

VALUE  OF  LAND 

The  farmer's  estimate  of  farm  land  values  is  very  often  not  based  on 
productive  value,  altho  this  factor,  together  with  the  distance  from  rail- 
road and  city  and  the  salability  of  the  farm,  usually  enters  into  the  appraise- 
ment. A  correlation  of  estimated  value  with  average  yields  will  show, 
in  a  measure,  the  extent  to  which  productive  ability  of  potato  land  enters 
into  its  evaluation.  App  (1916),  studying  the  factors  that  influence 
farm  profits  on  potato  farms  in  Monmouth  County,  New  Jersey,  found  a 
consistent  tendency  for  farm  acre  values  to  decrease  as  distance  from  the 
railroad  increased.  His  similar  conclusions  with  respect  to  crop  acre 
values  and  labor  income,  however,  do  not  seem  warranted  from  the  data 
given. 

The  figures  obtained  on  land  values  in  the  regions  surveyed  represent 
the  estimated  selling  value  of  potato  land  only.  A  more  important  factor 
than  the  distance  from  the  post  office,  which  was  ascertained  and  used 
in  making  this  estimate,  would  have  been  that  of  the  distance  from  the 
nearest  city,  village,  or  railroad. 

Apparently,  on  Long  Island,  land  valued  up  to  $550  an  acre  is  yielding 
an  increased  crop  with  the  increase  in  value  (table  9).  However,  it  is 
true  also  that  the  increase  in  land  values  is  accompanied  by  the  use  of 
more  seed  and  more  fertilizer,  and  by  more  spraying  for  blight.  These 
combined  factors  would  easily  account  for  the  consistent  increase  in  yield. 
The  farms  showing  a  land  value  of  over  $550  an  acre  are  located  prin- 
cipally in  Nassau  County,  at  a  considerable  distance  from  the  post  office, 
and  are  appraised  at  their  real-estate  value.  In  fact,  much  of  the  land 
has  been  sold  at  fabulous  prices  for  real-estate  purposes  and  is  now  rented 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1167 

TABLE  9.     RELATION  OF  VALUE  OF  LAND  TO  YIELD  ON  330  LONG  ISLAND  FARMS  IN  1912 


Value 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
distance 
from 
post 
office 
(miles) 

Amount 
of 
seed  used 
per  acre 
(bushels) 

Value  of 
manure 
and 
fertilizer 
per  acre 

Per  cent 
of 
farms 
using 
bordeaux 

Less  than  $250  
$250-8400  
$400-$550  

118 
132 

27 

147.0 
184.7 
196.7 

2.7 
2.3 

2.8 

12.1 
12.6 
13.0 

$30.24 
33.50 
35.24 

24 
45 
52 

$550  and  over  '.  .  .  . 

53 

191.9 

5.6 

12.7 

32.73 

11 

Total 

330 

Average 

175  5 

3  0 

12  5 

$32  40 

32 

back  to  the  original  owner  who  is  again  growing  potatoes  on  it.  Some- 
what less  seed  and  fertilizer  are  used  on  these  farms,  and  less  spraying  is 
done  on  them. 

In  Steuben  County,  potato  land  valued  up  to  $80  an  acre  gives  increased 
yields  with  the  increase  in  value  (table  10).     Tho  the  amount  of  seed  used 


TABLE  10. 


RELATION  OF  VALUS  OF  LAND  TO  YIELD  ON  360  STEUBEN  COUNTY  FARMS 
IN  1912 


Value 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
distance 
from 
post 
office 
(miles) 

Amount 
of 
seed  used 
per  acre 
(bushels) 

Value  of 
manure 
and 
fertilizer 
per  acre 

Per  cent 
of 

farms 
using 
bordeaux 

$25-$40 

46 

110  2 

5  3  ' 

9  6 

$  7  93 

4 

$40-$50 

111 

134  1 

4  2 

JO  4 

9  01 

6 

$50-$60 

76 

139  4 

3  6 

10  1 

10  86 

8 

$60-$70 

44 

144  4 

3  6 

10  4 

11  80 

o 

$70-$80 

42 

148  2 

2  9 

10  3 

12  29 

o 

$80  and  over 

41 

145  1 

2  5 

9  5 

10  31 

5 

Total  .  . 

360 

Average   . 

136  4 

3  8 

10  1 

$10  14 

5 

per  acre  is  about  the  same  thruout,  there  is  a  tendency  to  spend  more  in 
manure  and  fertilizer  for  the  higher-priced  land.     The  real  reason   for 


1168 


EARLE  V.  HARDENBURG 


this  is  doubtless  the  relative  cheapness  with  which  manure  and  fertilizer 
can  be  handled  by  the  growers  nearest  the  villages.  The  increased  yield 
of  the  higher-priced  land  may  be  due  in  part  to  this  increase  in  the  value 
of  manure  and  fertilizer  used.  Land  values  decrease  as  the  distance  from 
the  post  office  increases,  in  Steuben  County.  Distance,  in  fact,  may 
largely  determine  the  valuation  of  potato  land. 

In  Monroe  County,  as  in  Steuben  County;  the  yields  increased  with  the 
increase  in  land  values  (table  11),  the  yield  increase  being  accompanied  by, 


TABLE  11. 


RELATION  OF  VALUE  OP  LAND  TO  YIELD  ON  297  MONROE  COUNTY  FARMS  IN 
1913 


Value 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
distance 
from 
post 
office 
(miles) 

Amount 
of 
seed  used 
per  acre 

(bushels)  . 

Value  of 
manure 
and 
fertilizer 
per  acre 

Per  cent 
of 
farms 
using 
bordeaux 

$  50-  $100.  . 

27 

103  4 

4  3 

11  1 

$10  86 

19 

$100-  $150  V. 

145 

128  3 

2  6 

12  5 

10  09 

23 

$150-  $200  

69 

130  6 

2  3 

12  7 

12  02 

35 

$200-  $250  

56 

129.3 

2.3 

13.0 

14.10 

18 

Total 

297 

Average 

127  0 

2  6 

12  5 

$11  33 

24 

TABLE  12.    RELATION  OP  VALUE  OP  LAND  TO  YIELD  ON  303  FRANKLIN  AND  CLINTON 

COUNTY  FARMS  IN  1913 


Value 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 

(bushels) 

Average 
distance 
from 
post 
office 
(miles) 

Amount 
of 
seed  used 
per  acre 
(bushels) 

Value  of 
manure 
and 
fertilizer 
per  acre 

Per  cent 
of 
farms 
using 
bordeaux 

$  10-$  25.. 

29 

160  2 

4  2 

10  2 

$12  35 

0 

$  25-$  50  

105 

173  4 

3  5 

11  3 

13.73 

0 

$  50  -  $  75 

114 

189  0 

3  7 

12  9 

12  79 

2 

$  75  -  $100  . 

42 

178  2 

2  5 

12  3 

11  83 

0 

$100  and  over. 

10 

176  9 

1  6 

13  0 

15  02 

10 

Total  

300 

Average  

179  3 

3  4 

12  0 

$13.01 

1 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1169 

and  doubtless  largely  due  to,  an  increase  in  the  amount  of  seed  and  in 
the  value  of  manure  and  fertilizer  used.  Here  also  the  land  values  tend 
to  decrease  as  the  distance  from  the  post  office  increases. 

In  Franklin  and  Clinton  Counties  there  is  a  tendency  to  spend  more 
for  seed,  fertilizer,  and  spraying,  on  the  farms  having  the  higher- valued 
potato  land  (table  12).  This  expenditure  is  apparently  justified  on 
land  valued  up  to  $75  an  acre.  Above  that  point,  the  average  yield  did 
not  increase  even  with  increased  expenditure.  This  may  be  taken  as  an 
indication  that  such  land  was  valued  at  more  than  its  productive  ability 
would  justify.  These  more  valuable  farms  are  situated  near  Peru,  in 
Clinton  County,  and  are  thus  highly  valued  because  of  their  location  in 
the  apple  section  of  northern  New  York  rather  than  on  the  basis  of  their 
adaptability  to  potato  culture. 

SOIL 

It  has  not  been  possible  to  study  the  influence  of  soil  on  yield  on  Long 
Island  and  in  Franklin  and  Clinton  Counties.  Altho  Clinton  County 
has  been  soil-surveyed,  it  is  included  in  the  tabulations  with  Franklin 
County,  and  the  records  taken  were  insufficient  to  justify  the  making  of 
such  a  study  on  Clinton  County  alone.  The  Monroe  County  soils  map, 
published  by  the  United  States  Bureau  of  Soils,  has  been  used  in  correlat- 
ing yield  and  other  factors  with  the  soils  of  that  region. 

Professor  E.  0.  Fippin,  formerly  of  the  Department  of  Soil  Technology 
at  Cornell  University,  accompanied  by  the  writer,  made  a  reconnaissance 
soil  survey  of  the  surveyed  area  in  Steuben  County  in  the  summer  of  1916. 
Professor  Fippin's  familiarity  with  soil  mapping  in  New  York  enabled 
him  therefor  to  sketch  the  boundaries  of  the  various  soil  types  and  series 
on  the  topographic  sheets  previously  used  in  locating  the  surveyed  potato 
fields. 

Nearly  half  of  the  crop  in  Steuben  County  is  growri  on  the  Lordstown 
soil  series  at  an  average  elevation  of  1718.2  feet.  As  indicated  in  table 
13,  the  highest  average  yield  was  obtained  on  this  soil  series  in  spite  of  the 
fact  that  only  an  average  amount  of  seed  was  used  and  somewhat  less 
than  the  average  value  of  manure  and  fertilizer.  In  contrast  to  this, 
the  Volusia  soil  series,  located  on  the  hilltops  at  an  average  elevation  of 
1785.5  feet,  yielded  the  lowest  average  yield  of  any  series  in  spite  of  the 
fact  that  about  the  average  amount  of  seed  was  used  and  more  than  the 
average  value  of  manure  and  fertilizer.  The  principal  difference  between 
these  two  soil  series  lies  in  the  somewhat  darker  color  and  the  better 
ox'dized  condition  of  the  Lordstown  series.  It  is  true  that  the  soils  of 
this  region  become  lighter  in  texture  and  of  higher  gravel  and  stone  content 
as  the  valleys  are  approached.  This  condition  is  probably  blamable, 
at  least  in  part,  for  the  higher  percentage  of  blight  rot  on  the  heavier  soils 


1170 


EARLE  V.  HARDENBURG 


at  the  higher  elevations,  as  indicated  in  table  13.  Altho  very  little  spray- 
ing for  blight  was  done  in  1912,  it  was  noted  that  the  fields  which  were 
sprayed  returned  a  higher  average  yield  than  those  which  were  not  sprayed, 
irrespective  of  the  soil  type.  Apparently,  depth  of  planting  and  date  of 
planting  are  not  influenced  by  soil  type. 

TABLE  13.     RELATION  OF  SOIL  TYPE  TO  YIELD  ON  293  STEUBEN  COUNTY  FARMS  IN  1912 


Soil  type 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
unhar- 
vested 
yield 
per 
acre 
(bushels) 

Average 
value 
of 
manure 
and 
ferti- 
lizer 

Average 
amount 
of  seed 
used 
per 
acre 
(bushels) 

Per 
cent  of 
farms 
using 
bordeaux 

Average 
depth 
of 
planting 

(inches) 

Aver- 
age 
date 
of 
plant- 
ing 

Average 
elevation 
(feet) 

Volusia    silt    loam 
and  loam  
Lordstown  silt  loam 
Wooster       gravelly 
loam  
Rodman      gravelly 
loam  
Chenango  gravelly 
loam  

36 
151 

19 
59 

28 

115.9 

144.8 

126.9 
142.1 
140.4 

32.7 
25.2 

16.0 
24.0 
23.7 

$10.79 
9.35 

11.22 
11.76 
9.25 

10.2 
10.9 

9.2 
10.1 
11.0 

0 
6 

0 
2 

7 

3.4 
3.1 

3.2 
3.0 
3.1 

May  17 
May  19 

May  17 
May  22 

May  18 

1,785.5 
1,718.2 

1,637.9 
1,496.5 
1,364.6 

Total  

293 

Average 

139  6 

25  1 

$10  08 

10  6 

4 

3  1 

May  19 

1  642  8 

In  the  area  surveyed  in  Monroe  County,  four  soil  series  are  concerned — 
Ontario,  Dunkirk,  Clyde,  and  Genesee.  In  all,  fourteen  soil  types  are 
involved,  but  because  of  the  small  number  of  farms  on  some  of  these  types, 
only  those  shown  in  table  14  are  used  in  correlating  soil  with  yield  and 
other  factors.  On  the  basis  of  seed  used,  of  value  of  manure  and  ferti- 
lizer, and  of  percentage  of  farms  using  bordeaux,  the  Dunkirk  fine  sandy 
loam  and  the  Dunkirk  fine  sand  are  naturally  the  best  for  potatoes  from 
the  standpoint  of  yield,  among  the  types  considered.  Altho  in  1913 
nearly  half  of  the  crop  in  the  surveyed  area  was  grown  on  Ontario  fine 
sandy  loam,  under  at  least  average  cultural  treatment,  it  gave  the  lowest 
average  yield  per  acre  of  any  series  studied.  As  indicated  in  the  summary 
of  table  14,  the  soil  types  of  the  Dunkirk  series  seem  to  give  higher  yields 
than  those  of  the  Ontario  series.  The  average  amount  of  seed,  fertilizer, 
and  spraying  was  about  the  same  in  both  series.  Here,  as  in  Steuben 
County,  depth  and  date  of  planting  do  not  seem  to  be  influenced  by  any 
difference  in  soil  type.  The  average  elevation  of  the  two  soil  series  sum- 
marized is  almost  identical.  In  brief,  with  more  seed,  more  fertilizer, 
and  a  higher  percentage  of  area  sprayed  with  bordeaux,  the  Ontario  soils 
yielded  20  bushels  per  acre  less  than  did  the  Dunkirk  soils. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1171 

TABLE  14.      RELATION  OF  SOIL  TYPE  TO  YIELD  ON  253  MONROE  COUNTY  FARMS  IN  1913 


Average 

Average 

Soil  type 

Num- 
ber of 

Average 
yield 
per 

value 
of 
manure 

amount 
of  seed 
used 

Per 
cent  of 
farms 

Average 
depth 
of 

Average 
date 

Average 
elevation 

farms 

acre 
(bushels) 

and 
ferti- 

per 
acre 

using 
bordeaux 

planting 
(inches) 

of 
planting 

(feet) 

lizer 

(bushels) 

Dunkirk    fine    sandy 

loam 

20 

186  6 

$11  45 

12  4 

15 

2.9 

June  14 

659.3 

Ontario    fine    sandy 

loam  

124 

.122.0 

11.09 

12.6 

19 

2.9 

June     3 

595.2 

Dunkirk         gravelly 

loam  

32 

123.1 

9.83 

12.0 

25 

3.1 

June    7 

586.2 

Ontario  loam  

52 

124.2 

12.99 

13.0 

6 

3.3 

June    6 

582.0 

Dunkirk   gravelly 

sandy  loam  

11 

123.7 

9.01 

11.0 

27 

3.3 

June    8 

573.6 

Dunkirk  fine  sand.  .  . 

14 

137.2 

11.24 

12.4 

21 

3.7 

June    7 

515.0 

Total 

253 

Average 

128  3 

$11  31 

12  5 

17 

3  1 

June    6 

591  0 

Summary 

Ontario  series  

176 

122.7 

$11.65 

12.7 

27 

3.0 

June     5 

591.3 

Dunkirk  series  

77 

142.6 

$10.42 

12.0 

17 

3.2 

June  10 

590.5 

PLOWING 

The  study  of  plowing  aS  to  its  bearing  on  yield  is  treated  under  two  head- 
ings —  time  of  plowing  and  depth  of  plowing.  The  average  date  of  plow- 
ing was  obtained  by  averaging  the  actual  dates  of  plowing  for  each  region. 
It  is  recognized,  of  course,  that  this  date  will  vary  from  year  to  year, 
depending  on  seasonal  conditions.  The  only  region  in  the  State  in  which 
fall  plowing  was  done  to  any  appreciable  extent  was  Franklin  and  Clinton 
Counties.  To  determine  the  depth  of  plowing,  the  grower  was  in  each 
case  asked  to  give  his  estimate  of  the  actual  depth,  in  inches,  which  he 
plowed  for  potatoes. 

Time  of  plowing 

For  many  years,  such  advantages  as  increased  liberation  of  plant  food, 
elimination  of  injurious  insects,  and  improved  soil  texture,  have  been 
pointed  out  in  favor  of  fall  plowing.  Very  little  experimental  evidence 
has  been  presented,  however.  Dickens  (1914)  has  furnished  data  covering 
two  years  of  work  at  five  substations  in  Kansas,  all  showing  a  decided 
increase  in  yield  on  fall-plowed  as  compared  to  spring-plowed  land  for 
potatoes.  A  summary  of  the  data  on  the  season  at  which  potato  land 
was  plowed  in  each  of  the  surveyed  regions  in  this  study  is  given  in 
table  15: 


1172  EARLE  V.  HARDENBURG 

TABLE  15.    PER  CENT  or  POTATO  LAND  FALL-  OR  SPRING-PLOWED  IN  THE  AREAS  SURVEYED 


Franklin 

Long 

Steuben 

Monroe 

and 

Time  of  plowing 

Island, 

County, 

County, 

Clinton 

1912 

1912 

1913 

Counties, 

1913 

Fall  

1  5 

1  7 

0  33 

57.0 

Part  fall  and  part  spring  

2  1 

8  0 

0.00 

16.0 

Spring 

96  4 

90  3 

99  67 

27  0 

The  average  dates  of  spring  plowing  in  1912  for  Long  Island  and  for 
Steuben  County  were  April  3  and  April  29,  respectively.  The  average 
dates  of  spring  plowing  in  1913  for  Monroe  County  and  for  Franklin  and 
Clinton  Counties  were  May  15  and  May  12,  respectively.  No  speculation 
as  to  the  reason  for  the  greater  proportion  of  fall  plowing  in  Franklin  and 
Clinton  Counties  is  offered,  but  it  is  presumed  to  be  due  as  much  to  weather 
conditions  for  the  year  as  to  labor  competition  with  work  on  other  crops. 
The  comparative  yields  on  land  plowed  at  the  different  seasons  in  Franklin 
and  Clinton  Counties  are  shown  in  table  16: 


TABLE  16. 


RELATION  OF  TIME  or  PLOWING  TO  YIELD  ON  300  FRANKLIN  AND  CLINTON 
COUNTY  FARMS  IN  1913 


Time  of  plowing 

Num- 
ber 
of 

farms 

Average 
yield 
per  acre 

(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Average 
acreage 
of 
potatoes 

Fall 

171 

183  7 

12  4 

$12  81 

7  2 

Part  fall  and  part  spring  
Spring 

48 
81 

173.9 
173  2 

11.6 
11  5 

14.47 
12  46 

7.2 
7  2 

Total 

300 

Average  .  .  . 

179  3 

12  0 

$13  01 

7  2 

In  view  of  the  fact  that  about  a  bushel  more  of  seed  and  a  slightly  higher 
value  of  manure  and  fertilizer  were  used  on  the  fall-plowed  land,  the  dif- 
ference in  yield  of  10.5  bushels  per  acre  in  favor  of  fall  plowing  may  not  be 
entirely  due  to  a  difference  in  the  time  of  plowing.  There  is  no  indication 
that  fall  plowing  is  commoner  on  the  larger  potato  acreages,  since  the 
average  acreage  was  the  same  in  all  three  groups. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD*  OF  POTATOES     1173 


Depth  of  plowing   ' 

It  might  be  expected  that  a  crop  such  as  the  potato,  which  develops 
underground  and  is  subject  to  varying  conditions  of  soil  moisture  and 
soil  texture,  would  be  influenced  by  the  factor  of  depth  of  plowing.  How- 
ever, no  actual  experiments  with  this  problem  have  come  to  the  writer's 
attention.  Dickens  (1914)  states  that  shallow  plowing  has  given  the  best 
results  on  loamy  soil  at  the  Kansas  station.  Stone  (1905)  states  that 
at  the  Cornell  station,  deep  plowing  on  the  Dunkirk  gravelly  soil  gave  the 
best  results.  Generally  speaking,  shallow  plowing  has  been  recommended 
for  heavy  soils  and  deep  plowing  for  light  soils. 

The  possibility  of  drawing  definite  conclusions  from  a  study  of  a  factor 
depending  so  much  on  the  grower's  estimate  and  on  only  one  year's  results, 
is  necessarily  limited.  This  is  one  of  the  factors  that  for  its  ultimate  solu- 
tion must  depend  upon  carefully  controlled  experiments  on  a  given  soil 
type  in  each  region  concerned.  From  the  following  discussion  of  the  regions 
herein  considered,  it  would  appear  that  depth  of  plowing  is  an  important 
factor  only  on  soils  of  either  extreme  of  texture  —  deep  planting  increasing 
the  area  for  tuber  development  in  heavy  soils,  and  providing  for  planting 
at  the  moisture-table  depth  in  light  soils. 

Depth  of  plowing  on  Long  Island 

Altho  the  soils  of  Long  Island  are  noticeably  lighter  than  those  of  any 
other  potato  region  in  the  State,  a  marked  correlation  of  depth  of  plowing 
with  yield  is  evident  in  table  17.  An  increase  in  the  depth  of  plowing  was 
accompanied  by  the  use  of  more  seed  and  fertilizer  per  acre  and  a  greater 

TABLE  17.    RELATION  OF  DEPTH  OP  PLOWING  TO  YIELD  ON  328  LONG  ISLAND  FARMS  IN  1912 


Depth  of  plowing 
(inches) 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of 
seed  used 
'  per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Average 
number 
of  times 
sprayed 
with 
bordeaux 

Less  than  5 

26 

163  7 

11  4 

$30  01 

2  5 

5-6.. 

60 

162  9 

11  6 

30  53 

3  o 

6-7.. 

119 

173  8 

12  8 

32  15 

3  0 

7-8.. 

65 

174  1 

12  9 

33  65 

3  3 

8-9  

36 

188  6 

12  7 

35  26 

3  4 

9  and  over  

22 

202.1 

12.9 

32.13 

3.6 

Total  

328 

Average,  6.3  inches. 

175  6 

12  5 

$32  42 

3  1 

1174  EARLE  V.  HARDENBURG 

frequency  of  spraying.  These  factors  contributed  in  some  degree  to  the 
greater  yield  apparently  resulting  from  the  deeper  plowing.  In  answer 
to  the  question  whether  the  deeper  plowing  was  accompanied  by  deeper 
planting,  it  may  be  stated  here  that,  whereas  the  Long  Island  fields  were 
plowed  at  about  the  same  average  depth  as  those  of  the  similarly  light 
soils  of  Franklin  and  Clinton  Counties,  the  average  depth  of  planting  was 
deepest  on  Long  Island,  and  shallowest  in  Franklin  and  Clinton  Counties, 
of  the  four  regions.  Apparently,  deeper  plowing  on  Long  Island  is  to  be 
advised. 

By  virtue  of  its  descriptive  value  as  well  as  its  value  as  a  means  for 
measuring  correlation,  the  biometrical  method  has  been  applied  to  this 
factor  of  depth  of  plowing  for  Long  Island,  as  also  for  the  other  regions, 
and  the  result  is  shown  in  figure  132.  The  correlation  coefficient,  r,  here 

Yield  per  acre,  in  bushels 

OjpO*O  O  iO  Q  *O  O  *O  O  »O 

"jt^OCM  lO  b-  O  C^l  ^O  t^OtN 


.3  3 

&  4 
5 

||  « 

O  O 

.          H  O 

o-  9 

£  10 

&  11 

Q  12 


*  - 

& 

i 
o 

§ 

i 

£ 

i 

i 

i 

i 

s  s 

1 

1 

2 

i 

5 

4 

1 

9 

5 

2 

21 

2 

5 

15 

12 

6 

10 

5 

2 

1    2 

60 

1    2 

5 

11 

33 

16 

19 

11 

8 

8 

5 

119 

2 

5 

4 

16 

11 

12 

5 

7 

3 

65 

5 

5 

7 

3 

8 

4 

1 

1 

1    1 

36 

1 

1 

1 

8 

1 

2 

• 

1 

15 

1 

2 

1 

1 

1 

6 

0 

1 

1 

1        6      27        37        81        42        60        27        23        13          83     328 
r  =  0.159  ±  0.036 

FlG.  132.     CORRELATION  OF  DEPTH  OF  PLOWING  AND  YIELD  ON  328  LONG  ISLAND  FARMS  IN  1912 

has  the  value  0.159  d=  0.036.  Inasmuch  as  the  coefficient  is  positive  and 
is  more  than  three  times  its  probable  error,  it  shows  a  significant  degree  of 
correlation  between  depth  of  plowing  and  yield.  Present-day  biometri- 
cians  are  now  well  agreed  that  the  significance  of  a  coefficient  is  measured 
not  alone  by  its  absolute  value,  but  in  the  light  of  its  consistency  with 
coefficients  of  other  series  or  other  years  and  its  probable  error. 

Depth  of  plowing  in  Steuben  County 

In  contrast  to  soil  conditions  on  Long  Island,  the  soils  of  Steuben  County 
are  the  heaviest  of  any  of  the  four  regions.  Nevertheless,  a  rather  marked 
positive  correlation  between  depth  of  plowing  and  yield  is  shown  in  table 
18.  In  this  region,  as  on  Long  Island,  the  growers  who  plowed  deeper 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1175 


TABLE  18. 


RELATION  OF  DEPTH  OF  PLOWING  TO  YIELD  ON  360  STEUBEN  COUNTY  FARMS  IN 
1912 


Depth  of  plowing 
(inches) 

Number 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

4-  6      .                                                     

52 

125.8 

9.9 

$  8  59 

6-  8   ...                                              

258 

136.2 

10.1 

10  39 

8-10  ...... 

50 

149.4 

10.4 

10  54 

Total  .                 

360 

Average,  6.6  inches  

136.4 

10.1 

$10.06 

for  potatoes  were  inclined  to  plant  more  seed  and  to  use  a  greater  value  of 
manure  and  fertilizer.  The  difference  in  yield  of  nearly  24  bushels  per 
acre  resulting  from  a  difference  of  4  inches  in  depth  of  plowing  is  evidently 
due,  in  part  at  least,  to  the  increase  in  depth  of  plowing.  The  coefficient 
of  correlation  shown  in  figure  133  is  0.190  ±  0.034,  a  value  expressing 


Yield  per  acre,  in  bushels 


8 


g  24 

2 

1 

2 

2 

7 

|/S5 

1 

4 

7 

11 

14 

5 

2 

44 

£.S6 

2 

13 

31 

32 

23 

13 

12 

4 

3 

133 

J.S7 

1        2 

7 

18 

19 

26 

26 

18 

4 

4 

1 

126 

a  bc8 

1 

2 

5 

10 

12 

6 

6 

1 

3 

1 

47 

Q'S9 

1 

1 

1 

3 

2   5   26   64   73   78   52   38   9   10   0   2   0   0   1  360 
r  =  0.190  d=  0.034 

FlG.   133.       CORRELATION  OF  DEPTH  OF.  PLOWING  AND  YIELD  ON  360  STEUBEN  COUNTY  FARMS  IN 

1912 

significant  correlation.  Most  of  the  crop  in  this  region  is  grown  on  soils 
underlain  at  rather  shallow  depths  with  more  or  less  impervious  strata. 
Deeper  plowing  under  these  conditions  would  tend  to  enlarge  the  area 
adapted  to  maximum  tuber  development. 

Depth  of  plowing  in  Monroe  County 

The  soils  of  Monroe  County  may  be  considered  intermediate  in  texture 
between  those  of  Long  Island  and  those  of  Steuben  County.  As  a  rule,  they 
are  deeper  than  those  of  the  latter  region.  A  study  of  table  19  shows  no 


1176 


EARLE  V.  HARDENBURG 


TABLE  19. 


RELATION  OF  DEPTH  OP  PLOWING  TO  YIELD  ON  261  MONROE  COUNTY  FARMS 
IN  1913 


Depth  of  plowing 
(inches) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

4-7 

47 

136  4 

11  7 

$11  95 

7-8 

93 

134  2 

12  2 

10  97 

8-9.  .  . 

90 

132  5 

12  7 

12  05 

9  and  over   . 

31 

145  0 

14  5 

11  42 

Total  .    . 

261 

Average,  6.6  inches.  .  .          

135  6 

12  6 

$11  57 

apparent  relation  between  depth  of  plowing  and  yield.  With  approxi- 
mately the  same  fertilization  for  each  depth  of  plowing,  the  slight  tend- 
ency for  increased  yields  at  the  deeper  plowing  may  easily  be  attributed  to 
the  larger  amount  of  seed  planted. 

The  coefficient  of  correlation  shown  in  figure  134  is  0.006  ±  0.039.    Both 

Yield  per  acre,  in  bushels 


vO          O 
<N           iO 

^         ci 
<M 

i 

T—  1 

8 

T 

o 

126-150 

T 

176-200 

<M           CM            <N           <M           CO           CO 

£.    4 
IJ    5 

i 

1 

- 

1 

S         6 

2 

7 

12 

8 

12 

5 

4 

2 

^'S    7 

2 

10 

19 

24 

18 

13 

10 

2 

1 

1 

*•*>   8 

1         1 

16 

30 

11 

20 

13 

10 

3 

1 

M  9 

Q'S  10 

2 

4 
1 

8 

6 

9 
1 

1 
2 

1 

2 

1 

1 

2 

52 

100 

106 

33 

5 

299 


1    7   38   7(X  50   60   34   24   8   4   0    1    1 
r  =  0.006  d=  0.039  ' 

FlG.    134.       CORRELATION   OF  DEPTH   OF   PLOWING  AND    YIELD  ON  299  MONROE  COUNTY  FARMS 

IN  1913 

the  coefficient  and  its  probable  error  indicate  alack  of  relationship  between 
depth  of  plowing  and  yield  for  this  region.  Apparently  the  minimum 
depth  of  plowing  was  sufficient  for  maximum  production  in  Monroe 
County  soils. 

Depth  of  plowing  in  Franklin  and  Clinton  Counties 

The  figures  shown  in  table  20  indicate  that  depth  of  plowing  does  not 
influence  yields  in  Franklin  and  Clinton  Counties.    Tho  the  amount  of  seed 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1177 


TABLE  20. 


RELATION  OF  DEPTH  OF  PLOWING  TO  YIELD  ON  299  FARMS  IN  FRANKLIN 
AND  CLINTON  COUNTIES  IN  1913      \ 


Depth  of  plowing 
(inches) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

4-  5 

23 

175  5 

11  3 

$14  51 

5-  6 

70 

180  3 

11  4 

12  37 

6-  7 

118 

179  2 

12  3 

13  33 

7-  8 

52 

180  4 

11  9 

13.38 

8-10   . 

36 

179  6 

12.7 

12  07 

Total  

299 

Average,  6.2  inches 

179  3 

12  0 

$13  01 

planted  was  increased  slightly  as  the  depth  of  the  plowing  was  increased, 
the  amount  of  fertilizer  used  was  not  increased.  Consequently  there  would 
be  ample  opportunity  for  any  influence  of  depth  of  plowing  to  be  reflected 
in  the  yields  under  this  method  of  study.  The  coefficient  shown  in  figure 
135  is  0.028  db  0.039,  and  indicates  no  relationship  between  the  depth  of 
plowing  and  the  yield. 

Yield  per  acre,  in  bushels 


III 
r!? 


5 

,? 

c5 

i-H 
I 

o 

Q 

i—  i 

i—  i 
i 

3  • 

I 

7 

§ 

05 

L 

>o 

CM 

I 

1 
5 

2 

2 
1 
1 

1 

3 
13 
5 
4 

3 
11 
23 

8 
4 

1 

6 
16 
17 

8 
5 

8 
19 
32 
10 
6 
1 

6 
16 
10 
5 

2 
3 

8 
8 
4 
1 

1 

5 
5 

1 
2 

2 
2 

1 

26 


14 


23 
70 
118 
52 
32 

;4 

299 


12        26        50        52        76        38  . 
r  =  0.028  ±0.039 

FlG.     135.       CORRELATION     OF     DEPTH     OF     PLOWING     AND     YIELD     ON      299      FRANKLIN     AND 
CLINTON   COUNTY  FARMS  IN  1913 

MANURE  AND  FERTILIZER 

The  commercial-fertilizer  industry,  as  a  country- wide  enterprise,  began 
in  the  Eastern  States  and  dates  from  about  1860.  Previous  to  that  time, 
the  potato  crop  depended  for  its  plant  food  largely  upon  the  natural 
available  supply  of  the  soil,  supplemented  by  applications  of  barnyard 
manure.  Manure  has  been  recommended  by  many  experiment  stations 
as  perhaps  the  best  source  of  nitrogenous  plant  food  for  this  crop.  How- 
ever, as  the  acreage  increased  in  the  East  and  the  soils  became  more 


1178  EARLE  V.  HARDENBURG 

impoverished,  the  need  for  a  commercial  source  of  plant  food  became 
imperative.  Today  there  are  few  crops  which  require  more  and  respond 
be'tter  to  fertilizer  than  do  potatoes,  tho  even  yet  commercial  fertilizer 
is  used  very  little  on  the  newer  potato  lands  of  Michigan,  Wisconsin,  and 
Minnesota.  From  the  beginning  of  the  fertilizer  industry,  hundreds  of 
tests  have  been  conducted  by  the  eastern  state  experiment  stations  to 
determine  the  influence  on  the  yield  of  potatoes  of  such  factors  as  the 
amount  of  fertilizer  used,  its  analysis,  and  the  time  and  method  of  its 
application.  According  to  Whitney  (1910)v  1769  such  tests  were  conducted 
between  1868  and  1908,  a  period  of  forty  years.  Of  all  the  tests  made 
up  to  1908,  nearly  72  per  cent  fall  within  the  ten-years  period  from  1890  to 
1900.  Twenty-three  States  contributed  to  these  tests,  and  about  57  per 
cent  of  the  total  were  made  in  New  York,  Ohio,  and  New  Jersey.  Whitney 
states  that  it  is  impossible  to  draw  conclusions  even  from  an  average  of  simi- 
lar experiments  among  those  listed,  since  the  variation  in  the  yields  of  check 
plots  of  individual  experiments  sometimes  ranges  as  high  as  900  per  cent. 
The  crop  survey  has  been  found  to  have  its  limitations  in  the  study  of 
such  questions  as  best  analysis,  best  amount,  or  best  source  of  ingredients, 
of  a  fertilizer  to  be  used  for  potatoes.  It  is  generally  impossible  to  get 
information  from  the  grower  as  to  the  analysis  or  the  source  of  the  elements 
of  the  fertilizer  he  has  used.  Many  growers  who  were  .questioned  had 
been  more  impressed  by  the  brand  name  or  by  the  price  paid  for  the 
fertilizer  than  by  its  analysis.  An  attempt  to  correlate  the  amount  of 
fertilizer  per  acre  with  the  yield  resulting  was  found  impracticable  with- 
out knowledge  of  its  analysis,  owing  to  the  fact  that  large  applications  of 
a  cheap  fertilizer  might  be  no  more  than  equivalent  to  small  applications 
of  a  high-grade  fertilizer.  Furthermore,  many  growers  used  manure 
in  place  of  fertilizer,  or  vice  versa,  while  many  others  used  both  on  the 
same  acreage.  The  study  of  the  influence  of  manure  and  fertilizer  on 
yield  in  the  surveyed  regions  has  therefore  been  made  on  the  basis  of  the 
combined  value  per  acre  of  manure  and  fertilizer.  Estimates  of  the  value 
of  the  manure  used,  made  by  the  grower,  and  the  prices  he  paid  for  fertilizer, 
have  been  used.  In  determining  the  proportion  of  the  total  value  of  the 
manure  received  by  the  potato  crop,  depending  on  the  time  and  place  of 
its  application,  50  per  cent  of  its  value  was  charged  if  it  was  applied  directly 
to  the  potato  crop,  30  per  cent  if  it  was  applied  to  the  crop  just  preceding 
the  potatoes,  and  20  per  cent  if  it  had  been  applied  two  years  before 
potatoes.  This  evaluation  of  residual  manure  is  not  based  on  exact 
experimental  knowledge,  but  is  presumed  to  represent  the  approximate 
availability  of  stable  manure  for  successive  crops.  The  Department 
of  Agricultural  Economics  and  Farm  Management  at  Cornell  University 
estimates  that,  on  the  heavier  soils,  40,  30,  20,  and  10  per  cent  of  the 
value  of  manure  is  received  by  the  first,  the  second,  the  third,  and  the 
fourth  crop  after  its  application,  respectively.  On  lighter  soils,  which 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1179 


are  more  subject  to  leaching,  probably  a  charge  of  50  per  cent  to  the  first 
crop  would  be  more  nearly  correct.  A  uniform  basis  of  evaluation  has 
been  applied  in  this  study. 

Home-mixed  fertilizers 

Potato  growers  have  never  adopted  the  practice  of  mixing  their  own 
fertilizer,  even  in  the  regions  where  potatoes  are  raised  on  a  very  extensive 
scale.  The  advantage  of  using  home-mixed  fertilizers  has  usually  been  con- 
sidered, to  lie  in  a  saving  in  cost  rather  than  in  an  increase  in  yield.  Woods 
and  Bartlett  (1909)  compared  several  home-mixed  fertilizers  with  a 
common  ready-mixed  commercial  fertilizer  of  the  same  analysis.  They 
found  only  a  very  slight  advantage,  on  the  average,  in  favor  of  the  home- 
mixed  fertilizers. 

In  table  21  is  shown  the  relative  extent  to  which  home  mixing  is  practiced 
in  the  regions  surveyed.  These  figures  indicate  that  an  average  of  about 

TABLE  21.    PER   CENT   OF   GROWERS   USING   HOME-MIXED   FERTILIZER    ON  POTATOES 


Long  Island 

Steuben  County 

Monroe  County 

Franklin  and 
Clinton 
Counties 

6 

5 

10 

1 

5.5  per  cent  of  the  potato  growers  in  New  York  mix  their  own  fertilizer 
for  potatoes.  A  comparison  of  the  various  ingredients  which  constitute 
the  home-mixed  fertilizers  used  in  these  four  regions  is  given  in  table  22: 

TABLE   22.    PER  CENT  OF  GROWERS    USING  VARIOUS    INGREDIENTS    IN  HOME-MIXED 

FERTILIZERS 


Ingredient 

Long 
Island, 
1912 

Steuben 
County, 
.    1912 

Monroe 
County, 
1913 

Franklin 
and 
Clinton 
Counties, 
1913 

Nitrate  of  soda                                  

95 

26 

3 

100 

Acid  phosphate                             .      .  . 

90 

84 

100 

75 

JMuriate  of  potash                               .  . 

95 

62 

87 

100 

Tankage                                              .  . 

.95 

0 

10 

o 

Blood  and  tankage 

5 

0 

13 

o 

Dried  blood                                         .  . 

10 

0 

10 

o 

Bone  meal                                           .  . 

10 

5 

0 

25 

Nitrate  of  soda  and  dried  blood  .... 

0 

60 

10 

0 

Sulfate  of  potash 

5 

21 

13 

o 

Raw  rock  phosphate 

10 

5 

0 

0 

Fish  scrap 

55 

0 

0 

0 

1180  EARLE  V.  HARDENBURG 

The  percentages  shown  in  table  22  indicate  that  on  Long  Island,  nitrate 
of  soda  and  tankage  are  used  almost  universally  as  the  sources  of  nitrogen 
in  home-mixed  fertilizers.  As  is  typical  of  coast  regions,  much  fish  scrap 
also  is  used  for  its  nitrogen  content.  Acid  phosphate  is  the  principal 
source  of  phosphoric  acid,  altho  ten  per  cent  of  the  growers  who  mix  their 
own  fertilizers  on  Long  Island  use  bone  meal,  and  an  equal  number  use 
raw  rock  phosphate,  for  the  phosphoric  acid  supply.  Of  the  potash  supply 
95  per  cent  comes  from  muriate  of  potash,  and  the  remaining  5  per  cent 
comes  in  the  sulfate  form. 

In  Steuben  County,  nitrate  of  soda  and  dried  blood  used  together  was 
the  main  source  of  nitrogen,  no  tankage  being  used  by  the  five  per  cent  of 
growers  who  mixed  their  own  fertilizer.  Phosphoric  acid  was  obtained  by 
eighty-four  per  cent  of  these  growers  from  acid  phosphate,  and  five  per  cent 
obtained  it  from  bone  meal.  More  sulfate  of  potash  was  used  in  this 
region  than  in  any  of  the  other  regions  surveyed,  altho  62  per  cent  of  all 
the  potash  was  obtained  in  the  muriate  form. 

One-tenth  of  the  growers  visited  in  Monroe  County  mix  their  own 
fertilizer.  About  an  equal  number  of  these  growers  obtained  their  nitro- 
gen supply  from  dried  blood  and  from  tankage.  A  few  used  nitrate  of 
soda.  All  of  these  growers  obtained  their  phosphoric  acid  from  acid 
phosphate.  Muriate  of  potash  was  used  by  eighty-seven  per  cent  of  the 
growers,  v/hile  thirteen  per  cent  used  the  sulfate  form  for  potash. 

Only  one  per  cent  of  the  growers  in  Franklin  and  Clinton  Counties 
practiced  home  mixing.  These  men  used  only  nitrate  of  soda  for  nitrogen 
and  muriate  of  potash  for  potash.  Acid  phosphate  was  the  principal 
source  of  phosphoric  acid,  altho  a  little  bone  meal  was  used. 

Summarizing  for  the  four  regions,  it  is  seen  that  nitrate  of  soda  is  the 
commonest  source  of  nitrogen.  Generally,  however,  there  is  a  tendency 
to  mix  nitrate  of  soda  with  either  dried  blood  or  tankage  to  furnish  nitrogen 
in  both  a  quickly  and  a  slowly  available  form.  Acid  phosphate  and 
muriate  of  potash  are  the  principal  sources  of  phosphoric  acid  and  potash, 
respectively. 

Quantity  and  value  of  fertilizer 

The  optimum  amount  of  fertilizer  for  any  crop  necessarily  depends 
on  three  principal  factors:  the  available  supply  of  plant  food  in  the  soil, 
the  feeding  requirements  of  the  crop,  and  the  net  return  per  unit  invested 
in  fertilizer.  Of  these,  the  first  two  are  usually  measured  by  the  yield 
per  acre,  regardless  of  cost,  while  the  last  is  too  often  neglected.  Macoun 
(1905)  has  shown,  by  a  large  number  of  analyses,  that  a  200-bushel  yield 
of  potatoes  (exclusive  of  the  tops)  removes  an  average  of  40  pounds  of 
nitrogen,  20  pounds  of  phosphoric  acid,  and  70  pounds  of  potash,  per  acre 
of  soil.  This  is  about  the  same  amount  of  nitrogen  and  phosphoric  acid, 
but  twice  as  much  potash,  as  is  removed  by  comparable  yields  of  wheat 
and  corn. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1181 

Whitney  (1910)  summarized  the  many  fertilizer  experiments  on  potatoes 
in  this  country  as  to  the  influence  of  increasing  the  amount  of  fertilizer. 
So  far  as  nitrate  of  soda,  acid  phosphate,  and  muriate  of  potash,  used  singly, 
are  concerned  ^no  consistent  increase  in  yield  has  resulted  from  increasing 
the  amount  up  to  500  pounds  per  acre.  Increasing  the  amount  of  complete 
commercial  fertilizer  up  to  a  ton  and  more  per  acre  has,  on  the  contrary, 
consistently  increased  the  yields.  The  figures  shown,  however,  would 
indicate  that  the  increase  in  yield  caused  by  amounts  exceeding  a  ton  has 
not  been  profitable.  The  same  conclusions  can  be  drawn  regarding  the 
use  of  manure  in  these  experiments  up  to  an  amount  not  exceeding  20 
tons  per  acre. 

One  of  the  oldest  and  best  series  of  fertilizer  experiments  on  potatoes, 
covering  many  years,  was  begun  on  Long  Island  in  1895,  by  the  New  York 
Agricultural  Experiment  Station  at  Geneva  (Van  Slyke,  1895).  Com- 
parison of  the  yields  from  the  use  of  500,  1000,  1500,  and  2000  pounds  of 
fertilizer,  up  to  1898,  showed  that  it  was  not  profitable  to  use  more  than 
1000  pounds  per  acre.  The  tests  in  1898  showed  1500  pounds  to  be  the 
most  profitable  amount.  The  curve  of  relation  between  the  cost  of  fer- 
tilizer and  the  yield  of  potatoes,  altho  irregular,  shows  a  positive  correla- 
tion. Jordan  (1900),  reporting  on  a  continuation  of  these  Long  Island 
tests  in  1900,  showed  that  whereas  the  highest  yields  were  obtained  with 
2000  pounds  of  fertilizer  per  acre,  the  greatest  net  gain  from  the  crop 
resulted  when  only  1000  pounds  was  used.  Rane  and  Hall  (1904),  at  the 
New  Hampshire  station,  found  that  1500  pounds  of  commercial  fertilizer 
was  the  most  profitable  amount  to  use,  whether  or  not  normal  applica- 
tions of  manure  were  used.  Greater  amounts  of  fertilizer,  either  with  or 
without  manure,  were  not  profitable.  Kohler  (1910),  in  a  triplicate  series 
of  plots  conducted  at  the  Minnesota  station  in  1910,  showed  that  under 
Minnesota  conditions  it  would  not  pay  to  use  more  than  800  pounds 
of  fertilizer  per  acre,  and  in  most  of  his  tests  650  pounds  gave  the  highest 
gain.  The  gain  in  yield  from  the  elements  used  singly  was  almost  negli- 
gible, their  efficiency  showing  only  when  in  combination.  Kohler  recom- 
mended the  use  of  commercial  fertilizer  only 'when  the  supply  of  stable 
manure  became  insufficient  in  quantity.  The  experiments  of  Zavitz 
(1916)  at  the  Ontario  station,  covering  cooperative  and  station  tests  for 
five  and  three  years,  respectively,  show  a  gain  in  yield,  in  most  cases, 
resulting  from  an  increase  in  either  the  amount  or  the  value  of  the  ferti- 
lizer used.  Manure  and  fertilizer  in  combination,  and  manure  alone, 
gave  the  greatest  yields  per  acre  and  formed  the  cheapest  fertilizer  in 
both  sets  of  experiments,  not  counting  the  cost  of  freight  and  application. 
So  far  as  profit  is  concerned,  therefore,  the  results  of  the  Ontario  experi- 
ments must  be  discounted.  General  experience  has  shown  $h&t  the 
high  cost  of  handling  stable  manure  for  potatoes  on  a  large  scale  is  often 
prohibitive. 


1182 


EARLE  V.  HARDENBURG 


Manure  and  fertilizer  used  in  the  four  regions 

There  is  considerable  variation  in  the  amount  of  manure  and  fertilizer 
used  in  the  four  regions  surveyed.  On  Long  Island,  where  the  crop  is 
grown  successively  on  the  same  land,  it  is  necessary  to  use  large  amounts  of 
fertilizer  in  order  to  maintain  the  yields.  In  table  23  are  given  data 
concerning  the  use  of  manure  and  fertilizer  in  the  four  areas  surveyed.  It  is 
obvious  from  this  table  that  the  use  of  manure  on  potatoes  is  closely  asso- 
ciated with,  and  largely  dependent  upon,  the  dairy  industry. 

TABLE  23.     SUMMARY  OF  MANURE  AND  FERTILIZER  USED  IN  THE  FOUR  REGIONS  SURVEYED 


Average 

Per  cent 

value 

Per  cent 

Average 

Per  cent 

Average 

of 

per  acre 

of 

amount 

of 

amount 

growers 

of  manure 

growers 

of 

growers 

of 

Region 

using 

and 

using 

fertilizer 

using 

manure 

manure  or 

fertilizer 

fertilizer 

per 

manure 

per 

fertilizer 

on  farms 

on 

acre 

on 

acre 

or  both 

using 

potatoes 

(pounds) 

potatoes 

(tons) 

them 

Long  Island  . 

100 

$32.42 

100 

1,922 

21 

5.2 

Steuben  County  .... 

95 

11.00 

39 

270 

93 

12.2 

Monroe  County.  .  .  . 

100 

14.84 

65 

406 

98 

12.0 

Franklin  and  Clinton 

Counties  

99 

13.14 

76 

516 

79 

11.0 

The  first  column  of  percentages  .in  table  23  includes  not  only  the  growers 
who  applied  manure  or  fertilizer  directly  to  potatoes,  but  also  those  who 
applied  manure  or  fertilizer  to  the  crop  preceding  potatoes,  the  potatoes 
receiving  a  certain  percentage  of  value  from  the  residue.  On  this  basis, 
the  average  value  of  manure  and  fertilizer  used  on  Long  Island  was  more 
than  twice  that  for  the  Monroe  and  the  Franklin  and  Clinton  County 
areas,  and  nearly  three  times  that  for  the  Steuben  County  region.  The 
second  and  third  columns  of  percentages  in  the  table  represent  the 
growers  who  applied  fertilizer  and  those  who  applied  manure,  respectively, 
directly  to  the  potato  crop.  (The  reader  is  referred  to  page  1178.  for  the 
method  used  in,  evaluating  manure.)  It  may  be  noted  that  manure  is 
used  directly  for  the  potato  crop  by  almost  every  grower  in  Steuben  and 
Monroe  Counties,  while  on  Long  Island  only  one  grower  in  five  uses  it 
in  this  way.  Growers  on  Long  Island  do  not  find  it  so  practicable  because 
of  the  expense  of  handling  it  for  large  acreages,  the  danger  of  scab  infection, 
and  the  insufficiency  of  the  supply  for  their  fertilizer  needs.  In  Steuben  and 
Monroe  Counties,  manure  is  almost  invariably  applied  to  the  sod  land 
previous  to  plowing  for  potatoes.  It  is  so  applied  also,  but  to  a  lesser 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1183 


extent,  in  Franklin  and  Clinton  Counties,  altho  here  much  manure  is 
applied  to  new  seeding  and  some  is  applied  to  oats. 

It  is  evident  from  table  23  that  the  region  in  which  .only  a  small  propor- 
tion of  the  growers  use  fertilizer  on  potatoes  is  also  the  region  in  which  the 
least  fertilizer  is  applied  to  an  acre.  The  average  application  of  manure 
per  acre  in  each  region  shown  in  the  table,  is  reckoned  not  on  the  basis  of 
those  acres  alone  which  received  manure,  but  on  the  basis  of  the  total 
potato  acreage  of  those  farms  where  manure  was  applied.  Thus,  on  Long 
Island,  manure  is  applied  to  only  a  small  proportion  of  the  total  potato 
acreage  per  farm,  while  in  the  other  regions  most  of  the  acreage  is  covered. 
The  amount  per  acre  averages  nearly  10  tons,  tho  the  rate  varies  from 
10  to  20  tons. 

The  extent  to  which  fertilizer  and  manure  are  used  in  Monroe  County 
and  in  Franklin  and  Clinton  Counties  is  fairly  similar.  The  least  fertilizer 
is  used  in  Steuben  County.  Whether  more  could  be  used  profitably  in  any 
of  these  regions  is  discussed  in  the  subsequent  studies. 

Value  of  manure  and  fertilizer  on  Long  Island 

Inasmuch  as  the  amount  of  seed  used  has  been  found  to  be  a  very 
influential  factor  in  determining  yield,  this  factor  is  eliminated  as  far  as 
possible  in  the  studies  of  other  factors.  Therefore,  in  studying  the  influence 
of  the  value  of  manure  and  fertilizer  on  yield,  the  records  were  first  sorted 
into  groups,  according  to  the  value  of  manure  and  fertilizer,  and  were  then 
resorted  according  to  the  amount  of  seed  used,  as  shown  in  table  24: 


TABLE  24. 


RELATION  OF  VALUE  OF  MANURE  AND  FERTILIZER  TO  YIELD  ON  330  LONG 
ISLAND  FARMS  IN  1912 


Less  than  12 

From  12  to  14 

14  bushels  and 

bushels  of  seed 

bushels  of  seed 

more  of  seed 

Average  of  totals 

per  acre 

per  acre 

per  acre 

Value     of     manure 
and  fertilizer  per 
acre 

Num- 

Average 
yield 

Num- 

Average 
yield 

Num- 

Average 
yield 

Num- 

Average 
yield 

ber  of 

per 

ber  of 

per 

ber  of 

per 

ber  of 

per 

farms 

acre 

farms 

acre 

farms 

acre 

farms 

acre 

(bushels) 

(bushels) 

(bushels) 

(bushels) 

Less  than  $30  .  . 

67 

155.5 

43 

157.1 

13 

176.4 

123 

158.9 

$30-$40  

58 

172.1 

60 

174.0 

38 

196.2 

156 

180.1 

$40  and  over  

14 

182.7 

23 

187.5 

14 

222.1 

51 

198.0 

Total  

139 

126 

65 

330 

Average  . 

166.0 

170.2 



197.8 



175.5 

1184 


EARLE  V.  HAEDENBURG 


With  the  amount  of  seed  used  remaining  constant,  the  yield  was  increased 
in  every  instance  by  an  increase  in  the  value  of  manure  and  fertilizer  used. 
Furthermore,  the  yields  were  apparently  sufficiently  increased  by  the  use 
of  fertilizer  to  the  value  of  at  least  $40  an  acre,  to  make  such  applications 
profitable.  It  is  evident  that  the  maximum  limit  of  fertilization  in  1912 
did  not  exceed  the  point  of  optimum  profit. 

The  correlation  between  value  of  manure  and  fertilizer,  and  yield  per 
acre,  for  this  region  is  significantly  expressed  by  the  positive  coefficient 
0.244  d=  0.035  shown  in  figure  136. 


S     £ 


Yield  per  acre,  in  bushels 

O  <N  »O  t^  O  <> 


&       lo       ^ 

i 
§ 

£ 

<N 

T—  | 

3 

J. 

t^ 

i 

i 

is 

&    s 

<N           CO 

$11-415 

1 

1 

1 

3 

2 

6 

|      $21-$25 

9 

12 

21 

9 

13 

2 

3 

1 

70 

3        6 

9 

16 

10 

16 

6 

1 

2 

2 

71 

«§      $31-$35 

1        3        7 

6 

23 

14 

14 

11 

14 

4 

97 

-3  „  $36-$40 

3 

1 

12 

5 

10 

4 

4 

3 

2 

44 

«  g  $41-$45 

1 

3 

3 

2 

5 

3 

2 

4 

23 

2  *  $46-$50 

3 

2 

1 

1 

1 

8 

§  fe  $51-$55 

1 

1 

1 

1        1 

5 

§  a$56-$60 

1 

1 

2 

£      $61-$65 

1 

1 

2 

$66-$70 

0 

g      $71-$75 

0 

0      $76-$80 

1 

1 

1        6      27      38      81      43      60      27      23      13       8        3  330 

r  =  0.244  ±0.035 

FlG.  136.       CORRELATION   OF  VALUE   OF   MANURE   AND   FERTILIZER,    AND    YIELD,  ON   330   LONG 

ISLAND  FARMS  IN    1912 

Value  of  manure  and  fertilizer  in  Steuben  County 

In  Steuben  County  the  value  of  manure  and  fertilizer  has  been  studied 
in  a  similar  way.  As  appears  in  table  25,  however,  little  manure  and  fertili- 
zer is  used  here.  Altho  the  average  results  indicate  an  increase  in  yield 
from  the  use  of  as  much  as  $50  worth  of  manure  and  fertilizer  per  acre, 
the  increased  yield  from  applications  of  more  than  $20  worth  per  acre  was 
not  sufficient  to  tcover  the  extra  cost  of  the  fertilizer.  Therefore,  in  spite 
of  the  relatively  small  amount  of  fertilizer  applied  in  this  region,  there  may 
be  other  factors  that  limit  the  profit  possible  from  larger  applications. 
The  coefficient  of  correlation  between  this  factor  and  yield,  for  this  region, 
is  0.289  ±  0.033,  as  shown  in  figure  137. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1185 


TABLE  25. 


RELATION  OF  VALUE  OF  MANURE  AND  FERTILIZER  TO  YIELD  ON  155  FARMS 
IN  STEUBEN  COUNTY  IN  1912 


Value  of  manure 
and  fertilizer  per 
acre 

From  6  to  10 
bushels  of  seed 
per  acre 

From  10  to  .14 
bushels  of  seed 
per  acre 

From  14  to  18 
bushel  }  of  seed 
per  acre 

Average  of 
totals 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

$  4-$12.. 

25 
21 
11 

127.8 
141.3 
134.9 

41 

27 
17 

148.0 
162.4 
162.8 

5 
3 
5 

182.8 
287.1 
217.0 

71 
51 
33 

144.4 
160.0 
166.4 

$12-$20  

$20-$50  

Total  

57 

85 

13 

155 

Average  

133.9 

155.2 

213.7 

153.7 

Yield  per  acre,  in  bushels 

8     K     8     8    §    £ 

i     -     7    ~   1   ^ 

CO  i— I  CO  »-H          CO          i-H 


$  0-$  1 

$  1-$  5 

«  $  6-S10 

|  $11-115 

„  $16-$20 

a  $21-$25 

g  $26-430 

^  $31-$35 

*  $36-$40 

$41-$45 

$46-$50 


1 

1 

128 

20 

25 

15 

13 

5 

1 

90 

1   11 

22 

23 

29 

18 

12 

1 

2 

119 

3 

13 

8 

14 

8 

11 

2 

4      1        1 

65 

1 

1 

5 

7 

8 

4 

2 

2 

30 

1 

4 

4 

6 

1 

5 

1 

1 

23 

2 

1 

4 

1 

8 

1 

2 

1 

4 

1 

1 

0 

1 

1 

2 

1        3      24      61      70    72    52     38     9    10      0      2      00      1      343 
r  =  0.289  ±  0.033 

FlG.  137.       CORRELATION  OF  VALUE  OF  MANURE  AND  FERTILIZER,  AND  YIELD,  ON  343  STEUBEN 

COUNTY  FARMS  IN  1912 

Value  of  manure  and  fertilizer  in  Monroe  County 

The  influence  of  manure  and  fertilizer  in  Monroe  County  is  marked,  and, 
except  in  a  few  cases  where  too  few  records  were  available,  the  results  are 
consistent  under  constant  amounts  of  seed  used.  It  is  evident  from  table 
26  that  not  enough  manure  and  fertilizer  was  used  in  this  region  so  that  the 


1186 


EARLE  V.  HARDENBURG 


Is 


II  i 


CD   0 


o        £ 
^  « 

(M    °    03 


O    to    ® 

oo  § 


13Z 


KM 


02 

^  6 


I1"8! 


fa 

§3 
a 


1O  O5 

CO   T—  1 


s 


•^  CO  i 

r-l(M 


8 


3 


S 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1187 


point  of  diminishing  returns  was  reached.  The  yields  increased  sufficiently, 
up  to  the  highest  value  of  manure  and  fertilizer  used,  to  warrant  the  cost. 
Evidently  it  would  be  safe  to  recommend  the  use  of  larger  amounts  on 
potatoes  in  this  region.  The  positive  coefficient  of  correlation  shown  in 
figure  138  is  0.258  ±  0.036,  a  value  significant  and  consistent  with  the 
coefficients  for  the  other  regions. 


a     3 


Yield  per  acre,  in  bushels 

O          *O         O        *O        O        to        O 


§  $  1-$  5 

8  8  $  6-$10 

£  *  $11-$15 

g  fe  $16-$20 

S  J  $21-$25 

B  g  $26-$30 

o3  $31-$35 

«|  $36-$40 

S"  $41-$45 


1 

7 

17 

9 

7 

3 

1 

3 

18 

28 

20 

25 

14 

7 

3 

1 

1 

2 

10 

14 

11 

14 

8 

10 

4 

2 

1 

3 

9 

8 

11 

6 

6 

1 

1 

1 

3 

3 

1 

1 

1 

1 

1 

1 

\ 

1 

1 


38 


40111 


44 

121 

76 

43 

10 

5 

0 

0 

1 

300 


70      50    61    34    24 
r  =  0.258  =b  0.036 

FlG.  138.       CORRELATION  OP  VALUE  OP  MANURE  AND  FERTILIZER,  AND  YIELD,  ON  300  MONROE 

COUNTY  FARMS  IN   1913 

Value  of  manure  and  fertilizer  in  Franklin  and  Clinton  Counties 

A  constant  increase  in  yield  for  each  increase  in  value  of  manure  and 
fertilizer  used,  is  shown  in  table  27  for  the  Franklin  and  Clinton  County 

TABLE  27.     RELATION  OF  VALUE  OF  MANURE  AND  FERTILIZER  TO  YIELD  ON  290  FRANKLIN 
AND  CLINTON  COUNTY  FARMS  IN  1913 


Value  of  manure 
and  fertilizer 
per  acre 

Less    than    12 
bushels  of  seed 
per  acre 

From  12  to  14 
bushels  of  seed 
per  acre 

14  bushels  and 
more  of  seed 
per  acre 

Average  of 
totals 

Num- 
ber of 
farms 

Average 
yield 
per 

acre 
(bushels) 

Num- 
ber of. 
farms 

Average 
yield 
per 

acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Less  than  $10  
$10-$15...  
$15  and  over 

40 
40 
43 

149.2 
164.2 
170.4 

35 
39 

27 

182.1 
187.3 
190.0 

19 
26 
21 

174.8 
199.9 
221.7 

94 
105 
91 

167.1 
181.4 

188.2 

Total 

123 

101 

66 

290 

Average     .  . 

161.6 

186.2 

198.0 

178.8 

1188  EARLE  V.  HARDENBURG 

region.  The  increase  in  yield  obtained  by  growers  using  $15  worth  or  more 
of  manure  and  fertilizer,  over  that  obtained  by  growers  using  less,  was 
sufficient  to  warrant  the  extra  cost.  Only  twelve  growers  in  this  region 
used  more  than  $25  worth  of  manure  and  fertilizer  per  acre.  In  view  of 
the  decreasing  rate  of  increase  in  yield  between  the  last  two  groups, 
it  is  doubtful  whether  a  larger  expenditure  than  $25  an  acre  would  have 
shown  a  profitable  increase.  The  correlation  coefficient  for  this  factor  and 
yield,  as  shown  in  figure  139,  is  0.169  db  0.038.  This  indicates  a  significant 
relation,  but  one  not  so  strongly  marked  as  that  for  the  other  three  regions. 

Yield  per  acre,  in  bushels  . 

S»OO>-OQ*OO»OQ 
<M*Ot^O<NiOl^O 


20 
90 
111 
52 
13 
8 
1 
2 
1 

11    27    49    52    76    38    26    14     5   298 
r  =  0.169  ±0.038 

FlG.  139.        CORRELATION  OF  VALUE  OF  MANURE  AND  FERTILIZER,  AND  YIELD,  ON  298  FRANKLIN 
AND   CLINTON  COUNTY  FARMS  IN  1913 

Analysis  of  fertilizer 

The  average  potato  grower  of  New  York  is  even  yet  none  too  familiar 
with  the  significance  of  fertilizer  .analyses.  As  previously  stated,  it  was  diffi- 
cult to  get  information  as  to  the  analyses  of  the  brands  used,  many  of  the 
growers  having  been  more  impressed  by  the  price  paid  or  the  brand  name. 
Most  of  the  fertilizer  experiments  for  some  years  have  justified  the  practice, 
as  found  in  the  surveyed  regions,  of  using  fertilizers  in  complete  form  for 
potatoes. 

Aside  from  the  more  fundamental  physiological  processes  stimulated  by 
each  of  the  essential  plant-food  elements  in  plant  growth,  nitrogen  func- 
tions principally  in  producing  foliage,  phosphorus  in  hastening  maturity, 
and  potash  in  increasing  starch  production.  These  elements  in  combina- 
tion naturally  maintain  a  balance  of  value  in  successful  potato  production. 

Whitney  (1910),  in  summarizing  fertilizer  tests  on  potatoes  up  to  1908, 
showed  that:  (1)  there  has  been  a  consistent  increase  in  the  average  yield 
of  potatoes  with  the  increase  in  the  number  of  minerals  used  in  mineral 
fertilizers;  (2)  there  has  been  a  similar  increase  in  the  average  yield  from 
an  increase  in  the  number  of  minerals  used  in  combination  with  organic 


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A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1189 

fertilizers;  (3)  the  use  of  organic  fertilizers  in  combination  with  minerals 
resulted  in  higher  average  yields  than  resulted  from  mineral  fertilizers 
alone;  and  (4)  manure  and  commercial  fertilizers  produced  higher  average 
yields  than  any  other  type  of  fertilizer.  Ballou  (1910)  and  Gourley  (1910) 
substantiate  these  general  conclusions  in  reporting  the  results  of  a  fifteen- 
years  comparison  of  nitrate  of  soda,  acid  phosphate,  and  muriate  of  potash, 
used  both  alone  and  in  combination  on  potatoes.  These  tests  have  shown 
that,  altho  the  cheapest  cost  of  increase  per  bushel  was  obtained  from  the 
use  of  acid  phosphate  alone,  the  greatest  profit  per  acre  resulted  from  the 
use  of  the  complete  fertilizer.  The  Rothamsted  station,  in  England 
(Hall,  1905),  experimenting  for  twenty-six  years  and  using  five  varieties 
of  potatoes  on  a  series  of  ten  plots,  compared  the  yields  from  plots  receiv- 
ing ammonium  salts  alone,  nitrate  of  soda  alone,  superphosphate  alone, 
and  mixed  mineral  fertilizer.  The  average  yields  resulting  from  these 
treatments  varied  in  the  order  listed,  ranging  from  the  lowest  yields  with 
ammonium  salts  to  the  highest  yields  with  mixed  mineral  fertilizer.  Since 
these  plots  grew  potatoes  successively  for  twenty-six  years,  and  since 
potatoes  yielded  less  with  nitrogenous  fertilizers  than  with  mineral 
salts  alone,  it  was  concluded  that  "  the  potato  finds  a  difficulty  in  obtaining 
ash  constituents  rather  than  nitrogen  from  an  impoverished  soil."  Balen- 
tine  (1894)  conducted  greenhouse  experiments  to  compare  the  foraging 
power  of  the  potato  plant  for  phosphoric  acid,  with  that  of  other  crop  plants. 
He  used  identical  amounts  and  forms  of  nitrate  and  potash  fertilizer, 
but  varied  the  phosphatic  form.  He  compared  the  results  from  equivalent 
amounts  of  phosphoric  acid  in  mostly  insoluble  forms  with  those  from  the 
soluble  form  and  with  the  check  in  each  crop  series.  The  results  showed 
that  the  potato  plant  is  not  able  to  make  use  of  this  element  in  the  insoluble 
form  nearly  so  well  as  do  wheat,  corn,  peas,  and  turnips. 

Because  of  its  importance  in  stimulating  the  vigor  and  yield  in  the 
crop  and  in  satisfying  the  feeding  requirements  of  the  plant,  potash  had 
occupied  the  most  important  place  in  potato  fertilizers  up  to  the  time 
when  this  survey  was  made.  Rane  and  Hall  (1904)  compared  the  yields 
from  plots  containing  5,  10,  and  15  per  cent  of  potash,  respectively,  and 
those  from  plots  containing  no  potash  at  all.  They  found  that  at  the 
New  Hampshire  station,  altho  the  yield  was  increased  up  to  15  per  cent 
of  potash,  the  most  profitable  results  came  from  the  10  per  cent  of -potash 
in  a  complete  fertilizer.  Several  years  later  T.  C.  Johnson  (1916)  com- 
pared complete  fertilizers  differing  only  in  that  they  contained  3,  5,  and 
7  per  cent,  respectively,  of  potash.  He  obtained  the  best  results  from  the 
5-per  cent  fertilizer,  since  that  containing  7  per  cent  of  potash  seemed  to 
retard  maturity  and  decrease  the  yield.  Conner  (1906),  at  the  Florida 
station,  compared  complete  fertilizers  containing  7,  8,  9,  and  10  per  cent 
of  potash,  respectively.  Tho  this  was  but  a  one-year  test,  the  check 
plots  averaged  nearly  as  high  yields  as  did  the  plots  receiving  potash, 


1190  EARLE  V.  HARDENBURG 

which  indicates  'that  probably  potash '  is  not  a  limiting  factor  in  the  soil 
at  the  Florida  station. 

Under  the  recent  war  conditions,  growers  in  the  Eastern  States  were 
forced  to  do  without  potash  or  to  use  less.  Woods  (1918),  at  the  Maine 
station,  has  attempted  to  determine  the  possibility  of  obtaining  satis- 
factory yields  without  this  element.  His  average  results  for  the  three 
years  1915,  1916,  and  1917  show  that,  whereas  fairly  good  yields  have 
been  obtained  with  no  potash,  the  yield  has  been  increased  26  bushels 
an  acre  by  the  addition  of  3  per  cent  of  potash.  The  additions  of  5  and  8 
per  cent  of  potash  have  given  practically  no  increase  above  that  from  3 
per  cent.  The  high  percentage  of  potash  previously  used  in  Maine  was 
evidently  not  needed,  or  else  the  soil  had  become  temporarily  stocked 
with  a  surplus.  Chemical  analyses  have  shown  that  the  sandier  soils 
of  the  coastal  plain  are  more  deficient  in  potash  than  the  heavier  soils 
farther  inland.  This  fact  and  the  more  intensive  cultivation  of  potatoes 
probably  account  for  the  larger  amounts  of  potash  previously  used  in 
these  regions.  It  might  be  supposed,  therefore,  that  yields  of  potatoes 
cannot  long  be  maintained  without  this  constituent.  The  recent  studies 
of  Dr.  Oswald  Schreiner,  of  the  United  States  Department  of  Agriculture, 
on  potash  hunger  in  the  Aroostook  potato  region  in  Maine  and  in  the 
Norfolk  potato  truck  areas,  bear  out  this  conclusion.  The  writer  has 
recently  observed  marked  examples  of  potash  hunger  in  the  potato  fields 
of  Long  Island.  Evidently  the  shortage  of  potash  is  beginning  to  be  felt. 

Of  the  two  principal  forms  of  potash  —  muriate,  or  the  chloride  form, 
and  sulfate  —  the  muriate  has  always  been  the  more  commonly  used  on 
this  crop.  The  reasons  for  this  are  the  greater  cost  and  the  lesser  supply 
of  the  sulfate  form.  It  is  occasionally  stated,  tho  the  point  does  not 
seem  to  be  borne  out  by  much  experimental  evidence,  that  the  chlorine 
in  muriate  of  potash  is  detrimental  to  quality  in  the  potato.  There  has 
generally  been  little  difference  between  the  two  forms  as  to  the  yield 
resulting.  Rane  and  Hunt  (1897),  in  a  one-year  test,  used  87  varieties 
of  potatoes  and  obtained  a  very  slight  advantage  in  favor  of  muriate  of 
potash.  Many  years  later,  Brooks  (1914)  obtained  an  increase  in  yield  of 
11  bushels  per  acre  in  favor  of  the  sulfate  form,  with  an  additional  improve- 
ment in  quality. 

The  experiments  of  Conner  (1906)  show  results  from  the  use  of  various 
amounts  of  ammonia  and  of  phosphoric  acid  in  complete  fertilizer,  which 
not  only  are  inconsistent  but  also  show  average  yields  not  essentially 
different  from  those  from  the  check  plots.  T.  C.  Johnson  (1916),  com- 
paring the  results  from  2,  4,  and  8  per  cent,  respectively,  of  phosphoric 
acid  in  complete  fertilizer,  found  the  best  results  from  the  8-per-cent 
analysis.  His  results  with  varying  amounts  of  nitrogen  were  incon- 
clusive. Woods  (1918),  in  a  test  to  compare  nitrogenous  fertilizers  in 
combinations  of  nitrate  of  soda,  ammonium  sulfate,  and  organic  forms, 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1191 

thru  the  years  1914  to  1917,  inclusive,  found  practically  no  advantage 
for  any  one  form  over  another. 

Altho  many  different  analyses  of  fertilizers  were  used  in  1912  and.  1913 
in  the  surveyed  regions,  the  majority  of  growers  in  each  region  were 
buying  fertilizers  of  the  same  analysis.  In  table  28  are  shown  the  analyses 
of  the  fertilizers  in  commonest  use  at  that  time,  in  the  four  regions: 

TABLE  28.     COMMONEST  ANALYSES  OF  FERTILIZERS  USED  IN  THE  FOUR  REGIONS 

SURVEYED 


Rank 

Franklin 

Long 

Steuben 

Monroe 

and 

Island, 

County, 

County, 

Clinton 

1912 

1912 

1913 

Counties, 

• 

1913 

Used  by 

majority  

3-8-7 

2-8-10 

2-8-10 

2-8-10 

Second  in  amount  used  

4-8-7 

0-10-8 

0-10-8 

0-10-8 

Third  in 

amount  used  

5-8-5 

0-8-10 

0-8-10 

0-8-10 

Because  of  the  higher  percentage  of  nitrogen  in  the  fertilizer  used  on 
Long  Island,  this  region  has  used  a  higher  grade  of  fertilizer  than  any  of  the 
other  regions.  The  extra  nitrogen  has  been  used  to  maintain  this  element 
in  view  of  the  heavy  draft  on  it  caused  by  the  continuous  potato  culture. 
The  greater  use  of  manure  and  sod  residue  in  the  other  regions  has  furnished 
the  nitrogen  lacking  in  the  additional  fertilizer  used.  Aside  from  the 
nitrogen  content,  the  fertilizers  used  in  the  four  regions  have  been  similar 
in  analysis. 

Method  of  applying  fertilizer 

The  method  of  applying  fertilizer  to  potatoes  is  a  question  not  well 
worked  out  because  it  is  complicated  by,  and  dependent  on,  such  factors 
as  soil  type,  amount  of  fertilizer  used,  and  method  of  planting  the  crop. 
The  question  as  treated  here  relates  to  (1)  the  depth  of  applying  the 
fertilizer  relative  to  the  seed  pieces,  (2)  broadcasting  as  compared  with 
drilling,  and  (3)  time  of  application  relative  to  time  of  planting  the  crop. 
Obviously,  fertilizer  should  be  applied  at  that  depth  which  will  afford  it 
a  constant  supply  of  moisture  to  make  it  available  to  the  root  system  of 
the  potato  plant.  As  this  ddpth  is  less  in  heavy  soils  than  in  light  soils, 
both  fertilizer  and  seed  are  generally  applied  less  deeply  in  heavy  than  in 
light  soils.  Since  the  root  system  of  the  potato  plant  normally  develops 
laterally  to  a  radius  of  from  18  to  24  inches,  the  question  of  depth  of  appli- 
cation would  seem  more  important  than  that  of  whether  the  application 
should  be  by  drill  or  broadcast.  The  question  of  time  of  application  must 
depend  on  the  availability  of  the  fertilizer  used  and  the  seasonal  distri- 
bution of  rainfall. 


1192  EARLE  V.  HARDENS  URG 

Taft  (1892)  reported  the  comparative  yields  obtained  by  placing  ferti- 
lizer above  and  below  the  seed  piece  in  a  year  of  light  rainfall.  All  plots 
gave  a  gain  of  from  14  to  34  bushels  per  acre  in  favor  of  the  applications 
below  the  seed  piece.  Taft  and  Coryell  (1894)  reported  on  the  same 
test  covering  three  years  and  using  complete  fertilizer  on  three  varieties. 
The  results  were  all  in  favor  of  the  application  of  fertilizer  below  the  seed 
piece,  the  gain  being  from  25  to  40  bushels  per  acre.  Munson  (1894) 
compared  the  relative  efficiency  of  applying  fertilizer  by  the  Rural-New- 
Yorker  trench  system,  in  which  the  fertilizer  is  placed  in  mellow  earth  two 
inches  above  the  seed,  with  the  method  of  applying  it  to  the  surface  and 
harrowing  in.  Not  enough  difference  in  yield  was  obtained  to  pay  for 
the  extra  labor  of  making  the  trench  required  in  the  former  method. 

Rane  and  Hall  (1904),  replicating  plots  three  times,  compared  yields 
from  fertilizer  applied  above  and  below  the  seed,  both  with  and  without 
the  use  of  stable  manure.  They  obtained  in  all  cases  an  average  difference 
of  18  bushels  per  acre  in  favor  of  the  shallow  applications.  No  mention 
was  made  of  the  rainfall  available  that  year. 

Van  Slyke  (1895),  at  the  New  York  station,  compared  potato  yields 
grown  under  1000,  1500,  and  2000  pounds  of  fertilizer  per  acre,  respec- 
tively, applied  both  broadcast  and 'in  the  drill  row.  In  all  cases  in  which 
1500  pounds  or  less  was  used,  the  drill-row  applications  gave  the  better 
yield  by  about  10  bushels  per  acre.  When  2000  pounds  was  applied,  there 
was  a  difference  of  17.5  bushels  per  acre  in  favor  of  broadcasting.  This 
difference  was  probably  due  to  a  slight  injury  to  the  seed  pieces  caused 
by  contact  with  the  fertilizer  applied  in  the  drill  row,  for  the  stand  in  the 
latter  case  was  rather  uneven.  Rane  and  Hall  (1904),  using  1500  pounds 
of  fertilizer  per  acre,  compared  the  yields  obtained  by  applying  all  in  the 
hill  with  those  from  applying  half  in  the  hill  and  half  broadcast.  No 
check  plots,  and  only  three  plots  altogether,  were  used,  but  a  small  yield 
favoring  the  half-and-half  method  was  obtained.  The  gain,  however, 
was  due  to  a  larger  yield  of  culls  under  this  method.  Hall  (1905),  in 
reporting  the  experience  of  the  Rothamsted  station,  stated  that  phosphoric 
acid  and  potash  should  generally  be  applied  in  drills,  but  that  kainit 
should  be  applied  broadcast.  Jordan  and  Sirrine  (1910)  compared  these 
two  methods  of  application  at  three  points  on  Long  Island  during  the  years 
1905  to  1908,  inclusive.  Altho  the  differences  were  small  in  all  cases, 
there  was  an  average  gain  of  3  bushels  per  acre  in  favor  of  the  drill  method. 
Applications  of  500,  1000,  and  1500  pounds,  respectively,  were  compared 
under  each  method.  Woods  (1917),  using  1000  pounds  and  1500  pounds 
of  fertilizer,  respectively,  all  broadcast,  all  drilled,  and  a  part  used  either 
way  with  the  remainder  applied  after  the  crop  was  up,  found  differences 
favoring  the  drill  method  but  no  greater  than  might  be  expected  as  within 
experimental  error.  The  greatest  average  difference  between  the  two 
methods,  thru  the  years  1914  to  1916,  inclusive,  was  6  barrels  in  favor 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1193 

of  drilling.  Woods  concluded  that  nothing  is  to  be  gained  by  the  practice 
commonly  followed  in  Maine,  of  applying  some  fertilizer  along  the  row 
at  the  first  cultivation,  for  this  method  is  less  convenient  and  apparently 
no  more  efficient  than  applying  all  the  fertilizer  in  the  row  at  planting  time. 

Much  variation  in  the  method  of  applying  fertilizer  has  been  observed 
in  the  surveyed  areas.  Wherever  machine  planters  were  used,  the  ferti- 
lizer was  generally  applied  with  these.  On  Long  Island,  however,  where 
98  per  cent  of.  the  crop  was  planted  by  machine,  nearly  forty  per  cent  of  the 
growers  applied  the  fertilizer  broadcast,  using  a  grain  drill  or  a  lime  sower 
before  planting.  Tables  included  in  the  study  of  this  factor  show  that 
most  of  the  fertilizer  not  applied  thru  the  planter  was  applied  broadcast 
before  planting.  Generally  this  means  an  application  only  a  few  days 
prior  to  planting  the  crop. 

Without  exception,  on  Long  Island  a  higher  average  yield  resulted  from 
the  broadcasting  of  fertilizer  before  planting  (table  29).  This  difference  in 
favor  of  broadcasting  is  in  part  due  to  the  greater  quantity  of  seed  usually 
planted  when  this  method  is  used.  But  the  difference  is  sufficient  to  be 
significant.  Furthermore,  the  growers  in  the  first  fertilizer  group  who 
broadcast  the  fertilizer,  used  less  seed  than  did  those  who  applied  the 
fertilizer  in  the  drill  row.  Apparently  the  average  of  nearly  a  ton  of 
fertilizer  per  acre  used  in  this  region  in  1912,  was  more  efficient  when  broad- 
cast than  when  drilled. 

There  are  rather  too  few  farms  included  in  each  of  the  groups  for  Steuben 
County  (table  30)  to  aUow  any  definite  conclusions  to  be  drawn.  The 
differences  in  yield  apparently  due  to  difference  in  the  method  of  fertilizer 
application,  are  all  probably  due  mainly  to  the  indicated  difference  in  the 
amount  of  seed  planted.  This  leads  to  the  conclusion  that. for  Steuben 
County,  when  as  little  as  the  average  of  270  pounds  of  fertilizer  per  acre 
is  used,  it  is  fully  as  efficient  to  apply  it  all  in  the  drill  row  as  to  broadcast 
it  either  just  before  or  just  after  planting. 

Altho  the  differences  in  yield  between  the  two  methods  employed  in 
Monroe  County  were  small,  they  are  consistent  thruout  (table  31). 
Usually,  less  seed  was  planted  per  acre  by  .those  broadcasting  fertilizer 
before  planting  than  was  used  by  those  in  the  other  group,  yet  the  yields 
favor  the  method  of  broadcasting.  The  writer  is  unable  to  reconcile 
this  conclusion  with  that  for  Steuben  County.  Whether  the  exception 
here  favoring  broadcasting  when  an  average  of  only  406  pounds  of  fertilizer 
per  acre  was  used,  is  due  to  seasonal  rainfall  conditions,  is  purely  conjecture 
which  can  be  settled  only  by  controlled  experiments  over  a  protracted 
period. 

A  study  of  table  32,  weighing  the  influence  of  the  amount  of  seed  and  the 
value  of  the  fertilizer  used  in  Franklin  and  Clinton  Counties,  indicates 
that  here,  as  in  Monroe  County,  the  broadcasting  of  the  fertilizer  proved 
more  efficient  in  1913  than  the  application  of  it  in  the  drill  row.  It  is  of 


1194 


EARLE  V.  HARDENBURG 


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A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1195 


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1196 


EARLE  V.  HARDENBURG 


interest  to  note  that  more  than  half  of  the  211  growers  listed  here  applied 
their  fertilizer  by  the  broadcasting  method. 

The  study  of  the  methods  of  applying  fertilizer,  as  treated  in  this  paper, 
does  not  allow  any  definite  conclusions  to  be  drawn.  The  question  is 
apparently  one  of  local  application,  probably  depending  on  such  factors 
as  seasonal  rainfall,  amount  of  fertilizer  used,  and  soil  type,  as  previously 
suggested. 

Use  and  influence  of  lime  on  potato  land 

Lime  has  been  given  little  prominence  in  use  either  as  a  plant  food  or 
as  a  soil  amendment  for  potatoes.  This  is  due  to  the  fact  that,  being  an 
alkaline  agent,  its  use  is  conducive  to  the  development  of  common  scab 
(Actinomyces  chromogenus)  on  potato  tubers  whenever  the  causal  organism 
is  present  in  the  soil  or  introduced  on  the  seed  tubers.  Therefore  lime 
is  usually  applied  in  the  rotation  as  far  removed  from  the  potato  crop  as 
is  possible,  while  its  major  benefits  to  this  crop,  in  the  improvement  of 
soil  texture  and  the  growth  of  legumes,  are  as  well  accomplished.  Wheeler 
and  Adams  (1909)  reported  an  increase  in  the  proportion  of  tubers  of  mer- 
chantable size  from  the  use  of  lime.  There  seems  to  be  little  or  no  con- 
clusive evidence  available  that  lime  has  increased  the  yield  of  potatoes 
except  indirectly  thru  the  benefits  just  mentioned. 

In  spite  of  the  fact  that  lime  is  advised  for  most  potato  farms  outside 
of  the  surveyed  areas  of  Long  Island  and  Monroe  County,  very  few  growers 
reported  its  use  in  the  rotation  which  they  were  using  at  the  time  when 
the  survey  was  made.  A  summary  of  the  use  of  lime  and  its  place  in  the 
rotation  followed  in  the  surveyed  regions  is  given  in  table  33: 

TABLE  33.    USE  OF  LIME,  AND  ITS  PLACE  IN  THE  FOUR  AREAS  SURVEYED 


Region 

Per  cent  of 
growers  using 
lime  in 
rotation 

Average  number 
of  years 
removed  from 
potatoes 

Long  Island,  1912  

6 

3.4 

Steuben  County,  1912  

16 

3.1 

Monroe  County,  1913  

16 

3.0 

Franklin  and  Clinton  Counties,  1913 

7 

3.7 

Very  few  growers  apply  lime  regularly  in  their  rotation.  The  commoner 
practice  is  to  use  it  only  when  necessity  demands  it  as  a  means  of  producing 
legumes.  On  Long  Island,  where  potatoes  are  grown  for  so  many  suc- 
cessive seasons  on  the  same  land,  it  is  unsafe  to  use  lime  at  all.  The  number 
of  years  from  the  potato  crop  that  lime  is  applied,  indicated  in  table  33, 
shows  the  consistent  effort  of  the  growers  to  apply  it  as  far  from  potatoes 
as  is  possible,  in  order  to  avoid  scab. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1197 

ADAPTATION   AND   YIELD    OF   VARIETIES 

The  crop  survey  offers  one  of  the  best  means  of  determining  the  relative 
merits  of  potato  varieties  for  a  given  locality.  Too  often  the  experiment 
stations  have  made  generalized  recommendations  solely  on  the  basis  of 
the  performance  of  a  few  strains  tested  for  only  a  few  years  at  the  station 
grounds.  A  correct  knowledge  of  the  adaptability  of  various  types  and 
varieties  to  given  soil  and  climatic  conditions  can  be  obtained  only  by 
cooperative  controlled  tests  under  varying  conditions,  or  by  a  crop  survey  of 
the  performance  of  the  varieties  growing  over  a  wide  area  with  diverse  condi- 
tions. Nearly  every  state  experiment  station  in  the  United  States  has  at 
some  time  conducted  a  yield  test  of  potato  varieties,  the  results  of  which  are 
to  be  found  in  the  published  literature.  These  results  are  in  most  cases  of 
very  local  significance  and  pertain  only  to  the  strains  of  seed  that  were 
available  for  the  test.  Because  of  the  wide  variation  in  yield  of  the  dif- 
ferent strains  of  a  given  variety,  no  absolute  recommendations  for  any 
variety  should  be  made  on  the  basis  of  such  tests.  A  comparison  by  survey 
methods  of  the  average  yields  of  strains  of  the  varieties  within  a  region, 
furnishes  the  best  criterion  of  the  merits  of  such  varieties  for  that  region. 
Stuart  (1915)  has  classified  the  standard  American  varieties  into  groups 
containing  varieties  similar  in  tuber  and  foliage  characters.  It  is  now  well 
known  that  the  varieties  within  each  group  conform  fairly  closely  to  one 
another  in. their  adaptation  to  specific  soil  and  climatic  conditions.  This 
has  made  it  possible  to  determine  the  type  or  group  of  varieties  best  adapted 
to  certain  regions.  It  remains,  then,  only  to  choose  high-yielding  strains 
of  standard  varieties  within  this  group.  The  status  of  varieties  within 
each  of  the  surveyed  areas  has  been  studied  on  this  basis.  Varieties  and 
types  have  been  tabulated  in  the  order  of  their  extent  of  production  in 
each  region. 

Potato  varieties  on  Long  Island 

Of  the  four  regions  surveyed,  Long  Island  presented  the  greatest  varietal 
standardization  by  growing  the  fewest  varieties  and  the  fewest  types. 
Growers  in  this  region  are  convinced  that  varieties  of  the  Rural  group 
yield  less,  are  poorer  in  quality,  and  are  less  popular  in  the  New  York 
market,  than  varieties  of  the  Green  Mountain,  or  white-sprout,  type. 
Generally  speaking,  for  the  medium  late  crop,  only  varieties  of  the  Green 
Mountain  group  are  raised  on  Long  Island,  and  the  early  varieties  for 
this  region  are  chosen  from  the  Cobbler,  the  Early  Ohio,  the  Rose,  and 
the  Triumph  groups  (table  34). 

Altho  Green  Mountain  was  only  one  of  several  varieties  of  this  group 
grown  in  the  three  years  from  1911  to  1913  inclusive,  its  popularity  is  shown 
by  the  fact  that  two-thirds  of  the  average  total  acreage  during  this  period 
was  given  to  this  variety.  Irish  Cobbler  was  the  leading  early  variety 
produced,  and  most  of  the  acreage  of  this  variety  was  grown  in  Nassau 


1198 


EARLE  V.  HARDENBURG 


TABLE  34.     VARIETIES  GROWN  ON  330  LONG  ISLAND  FARMS  IN  1911,  1912,  AND  1913 


Variety 

j 

Color  of 
sprout 

Average 
number  of 
farms 
raising 
variety  in 
1911,  1912, 
and  1913 

Average 
yield  per 
acre  in 
1911  and 
1912 
(bushels) 

Per  cent  of 
total 
acreage 
grown  in 
1911,  1912, 
and  1913 

Green  Mountain  

White.. 

200.7 

180.4 

66.0 

Irish  Cobbler  

Pink  

119.7 

169.7 

13.0 

Carman  No   1 

White  . 

34  0 

189  3 

10  0 

Delaware 

White  .  .  . 

19  3 

210  5 

3  0 

Mills  Pride                         .    .    . 

White  

16  3 

164  4 

2  0 

Uncle  Sam  '                

Blue  

9  7 

220  4 

1  6 

Early  Ohio  .  .              

Pink  

9  7 

216  9 

1.6 

Norcross  ....        

White  

8.7 

212.1 

1.0 

World's  Fair  
Genesee  Seedling  
Rose  *  
Bliss  Triumph  
Early  Rose  

White  
White  
Pink  
Pink  
Pink  

3.7 
5.3 
5.7 
13.0 
7.0 

185.8 
248.1 
172.8 
126.9 
104.5 

0.5 
0.3 
0.3 
0.3 
0.2 

Bagley  

White  

4.3 

126.2 

0.2 

County.     A  summary  of  the  varieties  belonging  to  each  group,  as  classi- 
fied by  Stuart  (1915),  is  given  in  table  35: 

TABLE  35.     SUMMARY  or  TYPES  ON  330  LONG  ISLAND  FARMS  IN  1911  AND  1912 


Type 

Per  cent 
of  total 
acreage 
in 
1911 

Per  cent 
of  total 
acreage 
in 
1912 

Average 
yield 
per  acre 
in 
1911 
(bushels) 

Average 
yield 
per  acre 
in 
1912 
(bushels) 

Average 
amount 
of  seed 
used  in 
1912 
(bushels) 

Average 
value 
of 
manure 
and 
fertilizer 
in  1912 

Green  Mountain  . 

86 

84 

186  6 

179  7 

12  9 

$32.74 

Cobbler 

10 

12 

189  0 

157  2 

12  2 

32.00 

Triumph 

0 

1 

128  6 

11  4 

28.71 

Early  Ohio     . 

2 

1 

199  6 

231  5 

12  3 

44.99 

Rose 

1 

1 

166  8 

123  6 

13  4 

38.72 

Rural  ...                 .... 

1 

1 

227  7 

216  2 

10.1 

27.66 

Since  the  Green  Mountain  group  is  the  only  one  of  importance  in  this 
region,  no  comparison  of  relative  merits  is  made  between  the  types. 
Because  most  of  the  Early  Ohio  acreage  was  produced  near  or  at  Orient 
Point,  under  high  fertilization  and  with  ideal  moisture  conditions,  its 
high  average  yield  must  be  discounted  when  compared  to  that  of  the 
Cobbler  group.  Owing  to  its  high  average  yield  and  its  white  skin, 
Cobbler  has  proved  to  be  the  best  early  variety  for  this  section. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1199 

Potato  varieties  in  Steuben  County 

In  contrast  to  Long  Island,  Steuben  County  showed  the  least  standard- 
ization of  varieties  of  the  four  regions.  The  thirty-five  varieties  listed  in 
table  36  do  not  represent  all  that  were  found  in  the  region,  but  only  those 
comprising  an  average  of  at  least  0. 1  per  cent  of  the  total  acreage  for  three 
years. 

TABLE  36.     VARIETIES  ON  360  STEUBEN  COUNTY  FARMS  IN  1911,  1912,  and  1913 


Variety 

f 

Color  of 
sprout 

Average 
number  of 
farms 
raising 
variety  in 
1911,  1912, 
and  1913 

Average 
yield  per 
acre  in 
1911  and 
1912 
(bushels) 

Per  cent  of 
total 
acreage 
grown  in 
1911,  1912, 
and  1913 

Number  9  

Blue  

76.7 

143.5 

22.6 

Ruloff 

White     .      ... 

41  3 

126  5 

12  3 

Spaldings  Rose  4 

Pink 

66  6 

139  0 

11  2 

White  Pearl 

Blue 

20  7 

148  5 

6.6 

Sir  Walter  Raleigh  

Blue  

16.0 

156.8 

4.7 

Gold  Coin 

White     .      ... 

21  0 

135  0 

4  7 

Dooley  

Blue  

15.3 

148.8 

4.5 

Carman  No  3 

Blue 

15  3 

149  5 

4  2 

White  Giant  

Blue  

13.0 

135.3 

4.2 

State  of  Wisconsin 

White 

12  0 

134  4 

3  1 

Rural  New  Yorker  No  2 

Blue 

7  7 

134  4 

2  6 

Green  Mountain 

White 

7  3 

115  8 

1  8 

McKinley 

Blue 

8  0 

142  9 

1  7 

Pan  American 

Blue 

4  0 

121  3 

1  4 

Wliite  Granger 

Blue 

6  3 

147  2 

1.4 

Pearline 

Blue 

4  0 

114  9 

1  3 

German  Queen 

Pink 

4  7 

154  0 

1  1 

Planet 

Blue 

3  7 

126  8 

10 

Million  Dollar 

Blue 

3  0 

118  7 

1  0 

Early  M^anistee 

Pink 

5  7 

163  7 

0  9 

Uncle  Sam 

Blue 

3  0 

134  0 

0  9 

Charles  Downing 

White 

3  0 

118  2 

0  8 

American  Banner 

Blue 

2  7 

127  6 

0  8 

Goldstein 

Blue 

1  7 

118  0 

0  7 

Admiral  Dewey 

Blue 

2  ?'• 

167  2 

0  7 

California 

White 

1  7 

135  6 

0  7 

White  Mammoth 

White 

3  0 

133  8 

0  6 

Knoxall 

Blue 

3  7 

159  6 

0  5 

Carlisle 

Blue 

2  0 

156  0 

0  5 

Norcross 

White 

3  3 

143  0 

0  4 

Ward's  Seedling 

Blue 

2  7 

136  4 

0  3 

Scotch  Mane 

Pink 

2  3 

127  0 

0  3 

Mix  Best 

Blue 

2  0 

168  9 

0  2 

Early  Burpee 

Pink 

2  0 

108  3 

0  1 

Clustic  Beauty 

White     . 

0  7 

106  2 

0.1 

1200 


EARLE  V.  HARDENBURG 


It  is  significant  that  the  three  most  popular  varieties  of  this  region,  repre- 
senting nearly  half  of  the  average  total  acreage  during  1911  to  1913  inclu- 
sive, are  each  of  a  distinct  type.  Yet  each  may  have  its  proper  place  in 
Steuben  County  farming.  Number  9,  representing  a  high-yielding  strain 
selected  from  Rural  New  Yorker  No.  2,  heads  the  list  in  table  36  and  is  an 
ideal  blue-sprout  variety,  adapted  to  the  heavy  soils  and  narrow-valley  farms 
of  this  region.  Spaldings  Rose  4,  a  medium  early  variety  of  the  pink- 
sprout  type,  is  profitably  raised  for  a  special  seed  trade  with  the  Hastings 
potato  section  of  Florida .  Ruloff  is  a  variety  of  the  Green  Mountain  type 
which  is  well  adapted  to  the  lighter  soils  of  the  northern  part  of  the  county. 
Altho  there  may  be  this  apparent  justification  for  diversity  of  type,  there 
is  surely  no  justification  for  so  many  varieties.  Among  the  more  popular 
varieties  listed  in  the  table,  such  standard  varieties  as  Sir  Walter  Raleigh 
and  Carman  No.  3  would,  on  the  basis  of  yield,  appear  to  justify  their  more 
exclusive  use  in  this  region.  The  average  yield  of  the  more  popular 
standard  white-sprout  varieties  in  this  list  is  considerably  inferior  to 
that  of  the  Rural  varieties,  which  apparently  indicates  that,  in  general, 
this  type  is  not  so  well  adapted  here  as  is  that  represented  by  Number  9. 

A  comparison  of  the  types  produced  in  this  region  is  shown  in  table  37: 

TABLE  37.     SUMMARY  OF  TYPES  ON  360  STEUBEN  COUNTY  FARMS  IN  1911  AND  1912 


Type 

Per  cent 
of  total 
acreage 
in 
1911 

Per  cent 
of  total 
acreage 
in 
1912 

Average 
yield 
per  acre 
in 
1911 
(bushels) 

Average 
yield 
per  acre 
in 
1912 
(bushels) 

Average 
amount 
of  seed 
used  in 
1912 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 
in  1912 

Rural  

76 

75 

138.0 

142.4 

8.8 

$  8.90 

Green  Mountain  
Rose     . 

14 
9 

15 
9 

126.3 

113  8 

123.1 
142  2 

15.5 

9  7 

13.57 

8.89 

Hebron 

1 

1 

116  7 

194  4 

9.8 

12.82 

In  both  1911  and  1912,  the  Rural  group  of  varieties  outyielded  those  of 
the  Green  Mountain  type  by  an  average  difference  of  12  and  19  bushels 
per  acre,  respectively,  in  spite  of  the  fact  that  in  both  years  they  were 
grown  with  considerably  less  seed  and  fertilizer.  As  is  shown  later,  in 
table  42,  a  part  of  this  difference  was  due  to  a  greater  average  loss  per 
acre  in  the  unharvested  yield,  due  to  late  blight  rot,  in  the  Green  Mountain 
varieties.  It  therefore  appears  certain  that  the  Rural  type  of  potato  is 
better  adapted  to  the  prevailing  conditions  of  this  region. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1201 


Potato  varieties  in  Monroe  County 

Altho  a  very  large  number  of  varieties  were  grown  in  Monroe  County 
during  the  years  1912  to  1914,  inclusive,  it  is  seen  in  table  38  that  the 

TABLE  38.    VARIETIES  ON  300  MONROE  COUNTY  FARMS  IN  1912,  1913,  AND  1914 


Variety 
/ 

Color  of 
sprout 

Average 
number  of 
farms 
raising 
variety  in 
1912,  1913, 
and  1914 

Average 
yield  per 
acre  in 
1912  and 
1913 
(bushels) 

Per  cent  of 
total 
acreage 
grown  in 
1912,  1913, 
and  1914 

Sir  Walter  Raleigh  

Blue.  . 

59  3 

103  9 

20.7 

Carman  No.  3                        

Blue  

37  3 

128  2 

13.5 

Number  9  .                      

Blue  

45  3 

125  6 

12.3 

Peerless  Jr.                      

Blue 

21  0 

124  5 

8.3 

White  Giant      .                 

Blue. 

22  3 

129  9 

6.8 

Million  Dollar  .             

Blue     . 

21  0 

147  0 

6.1 

Perfection       .                         ... 

Blue 

17  0 

144  1 

5.5 

World's  Wonder  
White  Flyers 

Blue  
? 

22.3 
10  0 

138.9 
119  2 

4.5 

2.6 

White  Grant 

Blue 

14  0 

130  2 

2.4 

Rural  New  Yorker  No.  2  
Gold  Coin 

Blue.. 
White... 

7.7 
3  3 

124.1 
111  0 

2.3 

1.6 

American  Giant 

White  . 

6  3 

133  4 

1.4 

Granger 

Blue 

5  3 

109  2 

1.4 

Twentieth  Century 

Blue 

6  0 

164  9 

1.3 

Isle  of  Jersey 

Blue 

3  0 

110  8 

1.2 

Hundred  Fold 

? 

4  7 

141  2 

1.2 

Irish  Cobbler                         .    . 

Pink 

11  7 

124  6 

1.2 

Number  6 

Blue.  . 

4  7 

146  5 

1.2 

Pan  American 

Blue 

4  7 

138  5 

1.1 

McKinley 

Blue 

4  3 

156  5 

0.9 

Green  Mountain 

White  .. 

3  7 

174  9 

0.8 

Early  Michigan. 

Pink 

2  0 

115  0 

0.5 

Livingston 

Pink 

2  0 

90  6 

0  5 

American  Banner  

Blue  

2.0 

153.7 

0.4 

Number  8 

Blue 

>  -.'—  2'0 

150  8 

0.3 

prevailing  type  was  that  of  the  Rural  group.  Nearly  half  of  the  average 
total  acreage  of  this  region  during  the  years  1912  to  1914,  inclusive,  was 
planted  to  the  three  standard  blue-sprout  varieties,  Sir  Walter  Raleigh, 
Carman  No.  3,  and  Number  9.  Altho  the  three-years  average  yield  for  these 
varieties  was  slightly  less  than  the  average  yield  for  the  region  in  1913, 
it  would  still  seem  desirable,  for  the  sake  of  standardization,  to  select  high- 
yielding  strains  from,  and  to  retain,  these  few  varieties  to  the  exclusion  of 
most  of  the  other  varieties  of  the  Rural  type  listed  in  table  38.  It  is  note- 
worthy that  of  the  twenty-six  varieties  listed,  only  three  are  of  the  Green 


1202 


EARLE  V.  HARDENBURG 


Mountain  type.  The  relatively  light  seasonal  rainfall  and  the  heavy 
soils  of  the  Dunkirk  and  Ontario  series  have  resulted  in  the  survival  of 
Rural  varieties  at  the  expense  of  other  types.  Here,  as  on  Long  Island, 
Irish  Cobbler  was  found  to  be  the  leading  early  variety. 

The  status  of  varietal  types  in  this  region  is  summarized  in  table  39 : 

TABLE  39.     SUMMARY  OF  TYPES  ON  300  MONROE  COUNTY  FARMS  IN  1912  AND  1913 


Type 

Per  cent 
of  total 
acreage 
in 
1912 

Per  cent 
of  total 
acreage 
in 
1913 

Average 
yield 
per  acre 
in 
1912 
(bushels) 

Average 
yield 
per  acre 
in 
1913 
(bushels) 

Average 
amount 
of  seed 
used  in 
1913 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 
in  1913 

Rural  

94.0 

94.0 

141  4 

125.0 

12.8 

$11.48 

Green  Mountain  

3.4 

3.0 

153.3 

109.4 

14.3 

10.97 

Cobbler 

1  0 

1  0 

135  9 

117  1 

11  6 

12.75 

Hebrcn 

1  0 

0  5 

121  0 

138  8 

14  5 

9.65 

Rose 

0  3 

0  S 

128  6 

80  0 

10  6 

4.40 

Early  Michigan 

0  3 

0  7 

121  4 

100  0 

11  1 

5.56 

The  year  1913  was  one  of  low  seasonal  rainfall  in  Monroe  County, 
and  the  crop  suffered  from  the  drought.  As  shown  in  table  39,  varieties 
of  the  Green  Mountain  group  yielded,  in  that  year,  an  average  of  about 
15  bushels  per  acre  less  than  those  of  the  Rural  type,  in  spite  of  the  use  of 
more  seed  and  about  the  same  amount  of  fertilizer.  This  is  further  evi- 
dence that  varieties  of  the  Green  Mountain  group,  which  set  tubers  earlier 
than  do  those  of  the  Rural  group,  suffer  the  effects  of  reaching  their 
critical  growth  period  during  the  drought  season  of  midsummer  in  Monroe 
County. 

Potato  varieties  in  Franklin  and  Clinton  Counties 

Altho  more  varieties  are  grown  in  Franklin  and  Clinton  Counties  than 
on  Long  Island,  this  region  is  similar  to  the  lLong  Island  area  in  that 
nearly  all  the  varieties  were  found  to  be  of  the  Green  Mountain  type, 
as  is  shown  in  table  40.  A  notable  absence  of  early  varieties  was  found 
among  those  grown  from  1912  to  1914,  inclusive.  This  may  be  explained 
in  general  by  the  fact  that  the  possibilities  for  profitable  yields  are  much 
greater  in  the  main  crop  varieties. 

The  four  Green  Mountain  varieties  listed  at  the  head  of  table  40  —  White 
Beauty,  Selfic  Beauty,  World's  Fair,  and  Immense  —  comprised  more  than 
half  of  the  average  total  acreage  of  this  region  during  the  three  years  con- 
cerned. Type  has  become  well  standardized  here,  as  the  list  shows  only 
four  varieties  of  the  Rural,  or  blue-sprout  type,  the  remainder  all  being 
of  the  Green  Mountain,  or  white-sprout,  type.  While  these  four  Rural 
varieties  are  standard  varieties,  their  average  yield  per  acre  and  extent  of 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1203 


TABLE  40.    VARIETIES  ON  300  FRANKLIN  AND  CLINTON  COUNTY  FARMS  IN  1912,  1913, 

AND  1914 


Variety 

Color  of 
sprout 

Average 
number  of 
farms 
raising 
variety  in 
1912,  1913, 
and  1914 

Average 
yield  per 
acre  in 
1912  and 
1913 
(bushels) 

Per  cent  of 
total 
acreage 
grown  in 
1912,  1913, 
and  1914 

White  Beauty 

White  

47.3 

198.1 

16.4 

Selfic  Beauty 

White  

39.3 

200.7 

15.0 

World's  Fair 

White  

32.3 

179.9 

12.3 

Immense 

White  

17.7. 

154.5 

7.1 

White  Mountain  

White  

20.3 

199.1 

6.7 

Green  Mountain 

White   

18.7 

179.5 

6.6 

White  

14  0 

176.8 

4.7 

White  Lady               

White  

8.7 

197.9 

4.1 

Number  Q 

Blue 

11.3 

168.9 

4.0 

Mill's  Prize                  '  

White  

7.7 

189.9 

3.0 

Carman  No.  1  
National 

White  
White 

10.7 

6.7 

204.5 

184.8 

3.0 
2.4 

Rural  New  Yorker  No  2 

Blue 

6.3 

135.6 

2.0 

Lincoln                     

White  

6.3 

221.8 

1.9 

Scott 

? 

4.7 

160.6 

1.8 

Mountain  King 

White     .     .  . 

5.3 

199.7 

1.7 

Eggswaire 

White  . 

5.0 

165.6 

1.7 

Carman  No.  2  .        

Blue  

5.3 

191.9 

1.6 

Success                    

? 

3.7 

169.9 

1.2 

International 

White 

3.0 

197.3 

0.9 

Gold  Coin                   

White  

2.0 

147.7 

0.7 

Silver  Dollar  
Carman  No.  3               

White  
Blue  

4.7 
1.7 

187.4 
184.0 

0.7 
0.5 

production  do  not  seem  to  justify  their  competition  with  the  Green  Moun- 
tain type  A  comparison  of  these  two  types  for  the  region  in  1912  and 
1913  is  shown  in  table  41.  The  averages  for  1912  and  1913  show  that  with 


TABLE  41. 


SUMMARY  OF  TYPES  ON  300  FRANKLIN  AND  CLINTON  COUNTY  FARMS  IN  1912 
AND  1913 


Type 

Per  cent 
of  total 
acreage 
in 
1912 

Per  cent 
of  total 
acreage 
in 
1913 

Average 
yield 
per  acre 
in 
1912 
(bushels) 

Average 
yield 
per  acre 
in 
'1913 
(bushels) 

Average 
amount 
of  seed 
used  in 
1913 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 
in  1913 

Green  Mountain 

86 

92 

194.5 

183.8 

12.0 

$13.44 

Rural     . 

14 

8 

168.9 

164.9 

13.1 

14.42 

1204 


EARLE  V.  HARDENBURG 


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A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1205 


a  bushel  of  seed  less  and  a  dollar's  worth  less  of  fertilizer  per  acre,  the 
varieties  of  the  Green  Mountain  group  yielded  approximately  26  and  19 
bushels  per  acre  more,  respectively,  than  did  the  Rural  varieties;  Under 
the  cool  climatic  and  the  good  soil  conditions  of  this  region,  therefore, 
the  Green  Mountain  type  of  potato  is  the  more  profitable. 

Summary  of  varieties  in  all  regions 

A  comparison  of  the  principal  potato  groups  produced  in  all  four  regions 
during  the  years  for  which  survey  data  were  obtained,  is  shown  in  table 
42.  It  should  be  understood  that  no  specific  recommendations  for  a  given 
region  can  be  made  on  the  basis  of  the  comparisons  drawn  in  this  table. 
Certain  facts  of  interest,  however,  are  evident.  On  the  average,  the 
Green  Mountain  type  is  grown  under  more  favorable  climatic  and  soil 
conditions  than  the  other  types,  with  more  seed  and  more  manure  and 
fertilizer  per  acre.  Therefore,  for  the  State  as  a  whole,  the  Green  Mountain 
varieties  have  yielded  more  than  have  those  of  the  Rural  type.  The  table 
shows  that  in  the  blight  epiphytotic  of  1912  in  Steuben  County,  the  rotting 
of  the  white-sprout  varieties  in  the  field  exceeded  that  of  the  blue- sprout 
varieties  by  about  24  bushels  per  acre.  For  practically  the  same  reasons 
the  Cobbler  .type  has  outyielded  the  Rose  as  an  early  potato.  The  Early 
Ohio  owes  its  high  average  yield  in  1912  to  the  large  amount  of  seed  and 
fertilizer  used. 

SOURCE    OF   SEED 

In  the  mind  of  the  average  grower,  the  source  of  his  potato  seed  is  of 
small  concern  unless  of  necessity  he  is  compelled  to  periodically  change 
his  seed  stock  by  obtaining  it  outside  his  home  county.  The  only  section 
in  New  York  where  this  is  the  case  is  Long  Island.  In  table  43  are  shown 
the  sources  from  which  the  seed  supply  was  obtained  for  each  of  the  surveyed 
regions  in  1912  and  1913. 

TABLE  43.      SOURCE  OF  SEED  IN  THE  FOUR  REGIONS  SURVEYED,  IN  1912  AND  1913 


Region 

Farms  raising  their 
own  seed 

Farms  raising  part 
and  buying  part  of 
their  seed 

Farms  buying  all  their 
seed 

Number 

Per  cent 

Number 

Per  cent 

Number 

Per  cent 

Long  Island  
Steuben  County  .... 
Monroe  County  .... 
Franklin  and  Clinton 
Counties 

9 
358 

248 

215 

2.7 
99.4 

82.7 

71.7 

151 

*       2 
38 

50 

45.8 
0.6 
12.6 

16.6 

170 
0 
14 

35 

51.5 
0.0 

4.7 

11.7 

1206  EARLE  V.  HARDENBURG 

For  many  years,  the  Long  Island  growers  have  been  getting  most  of 
their  seed  from  Maine.  In 'recent  years,  the  decreasing  quality  of  Maine 
seed  has  resulted  in  the  use  of  some  seed  from  Vermont  and  New  York. 
Seed  for  the  other  three  regions  is  almost  entirely  used  within  the  county 
where  it  is  grown.  Occasionally  there  is  an  exchange  of  seed  between 
growers  within  the  neighborhood.  Long  Island  growers  have  learned 
that  it  is  not  profitable  to  use,  as  seed,  stock  that  has  been  grown  on  Long 
Island  for  more  than  one  year.  An  experimental  plot  at  Southampton 
is  shown  in  figure  131  (page  1158),  which  demonstrates  the  difference  in 
results  to  be  expected  between  new  stock  from  Maine,  and  Maine  stock 
grown  for  one  year  on  Long  Island.  The  45.8  per  cent  of  growers  on  Long 
Island  using  part  home-grown  seed  and  part  bought  seed,  shown  in  table 
43,  represent  the  extent  to  which  one-year  Long  Island  stock  originally 
imported  from  Maine  was  used  in  1912.  Most  of  the  seed  stock  from  Maine 
is  purchased  in  the  fall  to  be  shipped  in  the  very  early  spring,  since  storage 
facilities  on  Long  Island  are  very  meager  and  the  crop  is  planted  late  in 
March  or  early  in  April.  The  seed  stock  of  the  other  three  regions  is 
in  most  cases  stored  at  home  along  with  the  bulk  of  the  harvested  crop. 

,The  necessity  of  a  change  of  seed  on  Long  Island  is  due  to  several  factors. 
The  abnormally  long  period  between  harvest  and  planting,  much  oi  which 
includes  the  warm  or  hot  temperatures  of  late  summer  and  early  fall,  is 
not  favorable  to  potato  storage.  The  soil  temperature  of  this  region  during 
the  later  growing  season  is  apparently  so  high  as  to  seriously  reduce  the 
vigor  of  the  stock  for  seed,  in  spite  of  the  high  average  yields  obtained. 
The  problem  is  therefore  one  of  soil,  of  growing-season  and  storage  tem- 
peratures, and  of  length  of  storage  season  as  influencing  the  condition  of 
the  seed  at  planting  time. 

Emerson  (1914)  compared  yields  from  seed  cultivated  for  some  time 
in  Nebraska,  with  those  from  seed  raised  under  straw  mulch  and  from  seed 
recently  introduced  from  the  Red  River  Valley  of  North  Dakota.  He 
found  that,  whereas  the  cultivated  seed  of  Nebraska  rapidly  deteriorated 
under  hot  growing-season  temperatures,  by  mulching  with  straw  between 
planting  and  blossoming  time  he  was  able  to  so  reduce  the  soil  temperature 
as  to  maintain  vigor  and  obtain  practically  as  good  yields  from  seed  so 
raised  as  from  seed  just  introduced.  Stuart  (1913  a)  studied  the  influence 
of  environment  on  seed  by  introducing  seed  of  thirteen  English  varieties 
of  identical  origin  from  both  England  and  Scotland,  and  growing  it  con- 
tinuously in  Vermont  for  six  years.  The  average  increase  in  yield  of  the 
Scotch  seed  over  that  of  the  seed  from  England  varied  from  10.9  to  2713.9 
per  cent.  Results  similarly  striking  were  obtained  by  Macoun  (1905)  in 
four  varieties  grown  over  a  period  of  twenty  years  ,at  Ottawa.  He  had 
practiced  seed  selection  each  year  for  twelve  years  and  had  thus  been  able 
to  maintain  the  original  yield  of  the  stock.  Four  years  of  adverse  con- 
ditions followed,  during  which  the  yield  of  each  variety  decreased  decidedly. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1207 

Seed  of  these  same  varieties,  introduced  during  the  last  four  unfavorable 
years  from  Nappan,  Nova  Scotia,  and  subjected  to  the  same  unfavorable 
conditions,  maintained  its  yield  much  better,  showing  that  the  vigor  of 
northern-grown  seed  enabled  it  to  withstand  adversity  better  than  home- 
grown seed  similarly  treated.  Stone  (1905)  reported  an  experiment  by 
Fraser  in  which  tubers  that  had  been  stored  in  a  cool  cellar  until  May  1 
were  taken  out  and  stored  for  thirty-six  days  under  four  different  con- 
ditions. Yields  from  seed  stored  in  a  dark  cellar  at  from  50°  to  60°  F., 
in  a  coldframe  at  80°,  at  a  barn  window  at  out-of-door  temperatures,  and 
in  a  greenhouse  at  from  70°  to  90°,  showed  about  equally  good  results 
from  the  coldframe  and  the  barn-window  storage.  The  seed  stored  in  the 
dark  cellar  gave  decidedly  inferior  average  yields,  showing  that  moderate 
light  and  temperature  for  from  four  to  six  weeks  before  planting  improves 
production  over  the  usual  method  of  dark-cellar  storage  up  to  'planting 
time. 

The  potato  crop  of  Maine,  Vermont,  and  northern  New  York  is  almost 
invariably  harvested  before  the  maturity  of  the  plants.  The  vines  are 
usually  killed  by  frost.  Therefore  the  use  of  northern-grown  seed  for 
Long  Island  means  the  use  of  immature  seed;  and,  since  immature  seed 
is  closely  associated  with  the  dormancy,  or  rest  period,  of  the  potato 
tubers,  this  question  also  is  concerned.  According  to  Appleman  (1918), 
the  rest  period  varies  with  the  variety  but  is  fairly  constant  within  each 
variety.  Appleman  (1912)  has  shown  that  three  processes  go  on  in 
potato  tubers  during  the  rest  period:  (1)  respiration,  or  the  consumption 
of  sugar  by  reversion  to  carbon  dioxide  and  water;  (2)  conversion  of  starch 
to  sugar  by  diastase;  and  (3)  change  of  the  sugar  back  to  starch.  Since 
these  after-ripening  processes  are  greatly  influenced  by  temperature,  it 
follows  that  storage  conditions  have  much  to  do  with  the  condition  of  the 
seed  tubers  when  they  are  removed  from  storage  for  planting.  The  value 
of  seed  harvested  in  an  immature  condition,  which  has  been  shown  by 
the  experiments  of  Macoun  (1905),  Shepperd  and  Churchill  (1911),  Stuart 
(1913  b),  Zavitz  (1916),  Ballou  (1910),  and  Gourley  (1910),  is  due  prin- 
cipally to  the  fact  that,  the  seed  being  immature,  the  after-ripening 
processes  leave  it  in  a  less  devitalized  condition  than  that  of  seed  that 
has  entered  storage  fully  matured.  The  symptom  of  curled  skin  so 
common  at  harvest  time  on  northern-grown  potatoes  indicates  a  lesser 
degree  of  suberization  of  the  epidermis  than  occurs  in  mature  tubers. 
Appleman  (1914  and  1918)  has  shown  how  the  rest  period  may  be  shortened 
or  broken,  at  almost  any  time,  by  the  use  of  anaesthetics  or  of  oxidizing 
agents  to  facilitate  increased  oxygen  absorption.  He  further  showed 
(1918)  how  the  rest  period  of  the  southern  second-crop  seed  may  be  short- 
ened by  harvesting  the  seed  immature,  spreading  it  on  the  ground,  and 
covering  it  with  excelsior  or  burlap  to  prevent  suberization. 


1208 


EARLE  V.  HARDENBURG 


SUN-SPROUTING   OF   SEED 

The  practice  of  sun-sprouting  seed  is  one  which,  tho  recommended  for 
many  years  by  experiment  stations,  has  been  very  little  practiced  by 
potato  growers.  It  requires  the  bringing  of  the  seed  stock  from  dark 
cellars  into  a  place  of  moderate  light  and  higher  temperatures  for  a  period 
of  from  four  to  six  weeks  prior  to  planting.  The  main  objects  are  to 
improve  the  stands  and  increase  the  yields  by  (1)  the  development  of 
short,  thick,  green  sprouts  on  which  tuber-bearing  rhizomes  develop  close 
together,  (2)  the  opportunity  to  rogue  diseased  and  otherwise  inferior 
seed,  and  (3)  increasing  the  earliness  thru  the  starting  of  healthy  growth 
before  planting.  Flagg,  Towar,  and  Tucker  (1896),  in  Rhode  Island, 
using  duplicate  plots  and  harvesting  at  two  different  dates,  obtained 
increased  yields  from  sprouted  seed  ranging  from  32  to  54  bushels  per 
acre.  Fraser  (1912)  sun-sprouted  seed  of  the  varieties  Sir  Walter  Raleigh 
and  Carman  No.  3  for  thirty-six  days  prior  to  planting,  and  obtained 
increases  in  yield  ranging  from  0.9  to  73.7  per  cent.  Hutcheson  and 
Wolfe  (1917),  in  a  two-years  comparison,  obtained  a  difference  in  market- 
able yield  of  about  8  bushels  per  acre  in  favor  of  sun-sprouted  seed. 

The  extent  to  which  sun-sprouting  is  practiced  in  the  areas  surveyed  is 
shown  in  table  44.  Altho  earliness  is  much  desired  by  Long  Island  growers, 

TABLE  44.     GROWERS  WHO  SUN-SPROUTED  THEIR  SEED  IN  THE  FOUR  REGIONS  SURVEYED 


Franklin 

Long 

Steuben 

Monroe 

and 

Island, 

County, 

County, 

Clinton 

1912 

1912 

1913 

Counties, 

1913 

Number  of  growers  

0 

14 

166 

40 

Per  cent  of  growers  

0 

4 

55 

13 

no  one  was  found  who  sun-sprouted  seed  for  the  1912  crop.  Much  care  is 
used  in  choosing  seed  at  the  time  of  its  purchase  in  the  North.  The  several 
days  required  for  cutting  the  large  amount  of  seed  handled  by  the  average 
grower  in  this  region  affords  some  opportunity  for  sprout  development 
in  the  meantime.  Furthermore,  since  nearly  all  of  the  Long  Island  crop 
is  planted  by  machine,  care  would  be  necessary  that  none  of  the  sprouts 
so  formed  would  be  knocked  off  in  going  thru  the  planter. 

The  4  per  cent  of  growers  practicing  sun-sprouting  in  Steuben,  County 
in  1912  furnishes  too  small  a  number  to  study  the  influence  of  sun-sprouting 
on  yield  in  this  region. 

The  influence  of  sun-sprouting  on  yield  in  Monroe  County  in  1913  is 
shown  in  table  45.  The  difference  of  about  8  bushels  per  acre  in  favor  of 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1209 


TABLE  45.    RELATION  OF  SUN-SPROUTING  TO  YIELD  ON  166  MONROE  COUNTY  FARMS  IN  1913 


Treatment 

Number 
of 
farms 

Yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Not  sun-sprouted  

134 

121.7 

12.4 

$10.81 

Sun-sprouted                                            

166 

129.5 

12.6 

11.64 

Total                                                  

300 

Average                               <          

126.2 

12.5 

$11.28 

the  sprouted  seed  is  probably  no  more  than  might  be  due  to  the  increased 
amounts  of  fertilizer  and  seed  used  on  these  same  farms.  Therefore  it 
cannot  be  said,  on  the  basis  of  this  difference  in  yield,  that  in  1913  sun- 
sprouting  paid  for  the  extra  labor  involved. 

A  similar  study  of  this  factor  for  40  farms  in  Franklin  and  Clinton 
Counties  in  1913  is  shown  in  table  46.     Here  the  results  of  sprouting  were 


TABLE  46. 


RELATION  OF  SUN-SPROUTING  TO  YIELD  ON  40  FRANKLIN  AND  CLINTON  COUNTY 
FARMS  IN  1913 


Treatment 

Number 
of 

farms 

Yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Not  sun-sprouted 

260 

179  0 

11  4 

$13  25 

Sun-sprouted 

40 

180  6 

12  6 

11  65 

Total   .    . 

300 

Average 

179  3 

12  0 

$13  01 

even  less  marked  than  in  Monroe  County.  The  difference  of  1.6  bushels 
per  acre  in  favor  of  sun-sprouting,  while  within  experimental  error,  may 
easily  be  due  to  the  increased  amount  of  seed  used  by  growers  in  this 
group.  The  smaller  value  of  fertilizer,  however,  would  partially  offset 
the  difference  in  the  amount  of  seed  used. 

Tho  sun-sprouting  apparently  is  not  justified  by  the  results  shown  for  the 
last  two  regions  in  1913,  it  must  not  be  concluded  that  this  is  not  a  profit- 
able procedure  when  it  is  properly  done.  It  is  impossible  to  determine  by 
survey  methods  the  true  merits  of  this  phase  of  potato  growing,  because 
of  the  difficulty  of  taking  into  account  the  actual  methods  followed. 


1210 


EARLE  V.  HARDENBURG 


CHEMICAL  TREATMENT  OF  SEED 

The  chemical  treatment  of  seed  potatoes  to  rid  their  surfaces  of  the  organ- 
isms causing  common  scab  (Actinomyces  chromogenus)  and  rhizoctonia 
(Corticium  vaguum)  has  been  sufficiently  tested  scientifically  to  warrant  its 
practice  wherever  these  diseases  occur.  Tho  such  treatments  as  immersion 
in  corrosive  sublimate  or  formaldehyde,  or  fumigation  with  formaldehyde 
gas,  are  not  warranted  to  insure  the  crop  against  either  of  these  diseases 
in  the  following  crop,  yet  they  have  invariably  reduced  the  infection  to  a 
profitable  extent.  Ballou  (1910)  and  Gourley  (1910),  using  duplicate 
plots  of  untreated  seed,  seed  treated  with  formalin,  and  seed  fumigated 
with  formaldehyde  gas,  reduced  the  scab  infection  from  an  average  of 
58.5  per  cent  in  untreated  seed  to  16.7  per  cent  in  formalin-treated  seed 
and  to  18.4  per  cent  in  fumigated  seed.  The  writer  (Hardenburg,  1917) 
reported  a  reduction  of  rhizoctonia,  in  the  crops  of  fifty-eight  growers  in 
New  York  who  used  corrosive  sublimate,  to  1.8  per  cent  infection  as 
compared  with  12.7  per  cent  infection  of  the  crops  grown  by  the  remaining 
twenty-two  growers  considered.  He  reported  a  similar  reduction  of  scab 
infection,  thru  formalin  treatment  by  sixty-two  growers,  to  7  per  cent  as 
compared  with  10.7  per  cent  in  the  crops  grown  from  untreated  seed. 

In  spite  of  these  -tests  and  the  recommendations  based  on  them,  a  rela- 
tively small  proportion  of  growers  in  the  four  surveyed  regions  treat  their 
seed.  The  percentage  doing  this  in  each  region  is  reported  in  table  47: 


TABLE  47. 


PER  CENT  OF  GROWERS  TREATING  SEED  CHEMICALLY  IN  THE  FOUR  REGIONS 
SURVEYED 


Franklin 

Long 

Steuben 

Monroe 

and 

Treatment 

Island, 

County, 

County, 

Clinton 

1912 

1912 

1913 

Counties, 

1913 

Formalin 

1  0 

0  003 

7  3 

0  0 

Corrosive  sublimate  ... 

0  0 

0  000 

1  7 

0.0 

Formaldehyde  gas                      .    .    . 

1  0 

0  000 

0.0 

0.0 

Sulfur  

0.0 

0.000 

3.7 

0.0 

Total  

2.0 

0.003 

12.7 

0.0 

It  has  not  been  possible  in  this  study  to  correlate  the  apparent  need  of 
seed  treatment  with  the  actual  practice  as  indicated  in  this  table.  This  is 
due  partly  to  incomplete  data  from  the  four  regions,  and  partly  to  a  lack 
of  familiarity  with  diseases  on  the  part  of.  growers.  Such  treatment, 
however,  is  universally  recommended  because  of  the  attested  saving  to 
the  crop.  For  the  four  regions,  an  average  of  8.3  per  cent  of  the  growers 
reported  scab,  and  an  average  of  4.6  per  cent  reported  rhizoctonia,  in  the 
crop  from  which  these  data  were  taken. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1211 

INTERVAL    BETWEEN    CUTTING    AND    PLANTING 

An  interval  of  from  one  to  ten  days  sometimes  elapses  between  the 
time  when  seed  potatoes  are  cut  and  the  time  when  they  are  planted. 
Weather  conditions  unsuited  to  planting  after  the  seed  is  cut  sometimes 
make  this  delay  necessary,  while  in  some  sections  the  large  amount  of 
seed  to  be  cut  makes  it  seem  advisable  to  cut  it  several  days  early  in  order 
to  facilitate  the  earliest  possible  planting  of  the  crop.  To  some  extent 
this  is  the  case  on  Long  Island.  In  a  few  cases,  growers  have  cut  seed 
several  days  in  advance  of  planting  because  of  an  assumed  benefit  from  the 
drying  of  the  cut  surface  of  the  seed  pieces  to  be  planted.  The  object  of 
the  present  discussion  is  to  determine  the  relation  of  this  interval  of  time 
to  the  yield. 

Adams  (1887),  using  two  varieties  in  a  single-year  test,  obtained  an 
average  difference  of  26  bushels  per  acre  in  favor  of  planting  immediately 
after  cutting,  between  seed  cut  and  planted  fresh  and  seed  cut  twelve  days 
before  planting.  Green  (1888),  on  the  contrary,  using  three  varieties  in 
a  single-year  test,  reported  increased  yields  for  two  varieties  from  a  five- 
days  interval,  for  three  varieties  from  a  nine-days  interval,  and  for  one 
variety  from  a  twelve-days  interval,  over  the  yields  obtained  by  planting 
freshly  cut  seed.  These  tests,  he  reported,  agreed  with  those  of  Goff,  of 
Geneva,  who  recommended  the  benefits  of  drying  cut  seed  for  periods  not 
exceeding  ten  days  before  planting.  T.  C.  Johnson  (1912) ,  tho  not  reporting 
yields,  published  cuts  of  fields  planted  from  freshly  cut  seed  and  from  seed 
held  for  ten  days  after  cutting.  The  outstanding  feature  of  Johnson's 
test  of  this  factor,,  carried  out  under  carefully  controlled  conditions,  was 
the  strikingly  poorer  stand  grown  from  the  stored  cut  seed.  Zavitz  (1916) , 
in  a  test  covering  eight  years  at  the  Ontario  station,  obtained  an  average 
difference  of  8  bushels  per  acre  in  favor  of  planting  freshly  cut  seed  rather 
than  seed  held  for  only  four  or  five  days.  Furthermore,  he  obtained  an 
increase  of  1  per  cent  of  marketable  tubers  from  the  unstored  seed. 

As  previously  stated,  the  period  between  cutting  and  planting  is  fre- 
quently longer  on  Long  Island  than  in  any  of  the  other  three  regions 
surveyed.  The  relation  between  this  interval  and  the  yield  is  shown  in 
table  48.  Altho  the  relation  is  not  clearly  apparent,  it  is  evident  that  as 
the  interval  is  increased,  the  practice  of  dusting  is  also  increased.  Dusting 
tends  to  eliminate  any  of  the  deleterious  effects  caused  by  the  drying  out 
or  heating  of  seed  cut  and  stored  over  the  longer  periods  of  time.  The 
average  length  of  the  interval  between  cutting  .and  planting  in  this  region 
in  1912  was  5.7  days,  and  more  than  half  of  the  growers  dusted  their  cut 
seed. 

The  average  interval  between  cutting  and  planting  in  Steuben  County 
being  only  two  days,  little  correlation  between  this  factor  and  yield  would 
be  expected.  This  is  borne  out  by  table  49.  Also,  here,  as  on  Long  Island, 


1212, 


EARLE  V.  HARDENBURG 


TABLE  48. 


RELATION  OF  INTERVAL  BETWEEN  CUTTING  AND  PLANTING,  TO  YIELD,  ON 
272  LONG  ISLAND  FARMS  IN  1912 


Interval 

(days) 

Number 
of 
farms 

Yield 
per  acre 
(bushels) 

Per  cent 
of 
growers 
dusting 
cut  seed 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value 
of  manure 
and 
fertilizer 

Less  than  2.  ... 
2-3 

39- 
33 

161.4 
185  4 

41 
55 

12.0 

12  8 

$32.69 
31  73 

3-4     . 

52 

183  5 

46 

12  5 

33  33 

4-5  

32 

171  1 

59 

12  0 

30  45 

5-7  

13 

195  4 

46 

12  5 

32  39 

7  

43 

178  4 

56 

12  5 

32  41 

More  than  7  

60 

177  3 

73 

12  9 

33  53 

Total  

272 

Average,  5.7  days  

180  0 

57 

12  6 

$32  62 

TABLE  49. 


RELATION  OF  INTERVAL  BETWEEN  CUTTING  AND  PLANTING,  TO  YIELD,  ON 
354  STEUBEN  COUNTY  FARMS  IN  1912 


Per  cent 

Average 

Average 

Interval 

(days) 

Number 
of 
farms 

Yield 
per  acre 
(bushels) 

of 
growers 
dusting 

amount 
of  seed 
used 

value 
of  manure 
and 

cut  seed 

.  (bushels) 

fertilizer 

Less  than  1  

103 

125.0 

6 

10.0 

$  8.65 

1-2  

84 

145.3 

14 

10.5 

10.27 

2-  3.  

82 

140  4 

11 

10  1 

11  39 

3-5  

55 

132.4 

25 

9  9 

10  21 

5-15  

30 

149.6 

27 

10  2 

11  62 

Total 

354 

i 

Average,  2  days 

136  6 

*       14 

10  1 

$10  17 

dusting  was  commonest  where  the  interval  between  cutting  and  planting 
was  the  greatest.  This  being  true,  the  average  yields  for  each  group 
reported  in  the  table  appear  to  vary  according  to  the  average  amounts  of 
seed  and  fertilizer  used,  rather  than  according  to  the  length  of  the  interval 
between  cutting  and  planting. 

The  average  interval  between  cutting  and  planting  in  Monroe  County 
was  2.2  days,  as  shown  in  table  50.  The  range  in  interval  was  too  small 
to  show  any  marked  influence  of  this  factor  on  yield.  In  the  main,  dusting 
was  commonest  where  the  interval  was  the  greatest.  As  in  Steuben 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1213 


TABLE  50.     RELATION  OF  INTERVAL  BETWEEN  CUTTING  AND  PLANTING,  TO  YIELD,  ON 
260  MONROE  COUNTY  FARMS  IN  1913 


Interval 

(days) 

Number 
of 
farms 

Yield 
per  acre 
(bushels) 

Per  cent 
of 
growers 
dusting 
cut  seed 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value 
of  manure 
and 
fertilizer 

Less  than  1 

58 

141  ,7 

7 

.    13  1 

$11  68 

1-2  

66 

145:3 

21 

13.0 

13.32 

2-3 

64 

121  8 

22 

12  6' 

10  80 

3-4  

42 

132  »0 

10 

12.1 

10  79 

4  and  more 

30 

135  2 

27 

11  6 

10  87 

Total 

260 

Average,  2.2  days 

135  7 

17 

12  6 

$11  66 

County,  the  amount  of  seed  and  fertilizer  used  was  so  influential  as  to 
obscure  any  slight  influence  that  the  factor  of  the  interval  between  cutting 
and  planting  might  have  had. 

Growers  in  the  Franklin  and  Clinton  County  areas,  like  those  of  Steuben 
and  Monroe  Counties,  aim  to  plant  their  seed  as  quickly  as  possible  after 
cutting.  The  average  interval  in  1913  was  only  two  days.  Since  only 
about  ten  per  cent  of  the  growers  held  seed  as  long  as  four  days  after  cutting,* 
no  significant  relation  of  this  factor  to  yield  was  found.  However,  as 
shown  in  table  51,  the  most  dusting  was  done  by  the  growers  who  held 
their  seed  the  longest. 


TABLE  51. 


RELATION  OF  INTERVAL  BETWEEN  CUTTING  AND  PLANTING,  TO  YIELD,  ON 
264  FRANKLIN  AND  CLINTON  COUNTY  FARMS  IN  1913 


Per  cent 

Average 

Average 

Interval 

Number 

Yield 

Of 

amount 

value 

(days) 

of 
farms 

per  acre 
(bushels) 

growers 
dusting 

of  seed 
used 

of  manure 
and 

cut  seed 

(bushels) 

fertilizer 

Less  than  1    . 

113 

174  2 

4 

12  2 

$13  27 

1-2  

51 

193.1 

2 

12.4 

12.42 

2-3  

37 

178  7 

5 

11  4 

13  14 

3-4.  .  .      . 

30 

173  6 

0 

11  6 

12  64 

4  and  more    .    . 

33 

186  5 

30 

12  6 

15  11 

Total  

264 

Average,  2  days 

180  1 

6 

12  0 

$13  32 

1214 


EARLE  V.  HARDENBURG 


DUSTING    CUT    SEED 

Dusting  of  cut  seed  has  for  its  objects  the  prevention  of  drying  out  by 
undue  bleeding  of  the  cut  surfaces,  and  the  prevention  of  heating  which 
may  occur  in  cut  seed  stored  in  large  volume  under  conditions  of  poor 
ventilation.  Dusting  is  not  commonly  practiced  except  when  conditions 
require  the  storage  of  large  quantities  of  cut  seed  for  several  days  before 
planting,  as  on  Long  Island  in  1912.  Stone  (1905)  compared  the  yields 
from  five  varieties  cut  only  one  or  two  days  before  planting,  one  lot  of 
each  variety  being  dusted  with  land  plaster  and  the  other  lot  not  being 
dusted.  Four  of  these  varieties  gave  increased  yields  from  dusting, 
ranging  from  5  to  26  bushels  per  acre,  while  the  fifth  showed  a  decreased 
yield  of  7  bushels.  The  writer  believes  that  a  greater  interval  between 
cutting  and  planting  would  have  resulted  in  a  greater  increase  in  yield  due 
to  dusting.  Zavitz  (1916)  reported  on  an  average  of  twenty-two  tests, 
covering  five  years,  in  which  yields  from  undusted  freshly  cut  seed  were 
compared  with  yields  from  seed  treated  with  land  plaster  and  with  slaked 
lime.  In  all  these  tests,  the  seed  was  planted  immediately  after  cutting 
and  dusting.  The  average  yield  from  the  seed  treated  with  plaster  was 
23.6  bushels  per  acre  higher  than  that  from  the  untreated  seed,  and  the 
average  yield  from  the  seed  treated  with  lime  was  9.8  bushels  per  acre  more 
than  that  from  the  untreated  seed.  In  another  experiment,  in  which  the 
effects  of  treating  cut  seed  with  road  dust,  with  ground  brick,  and  with 
land  plaster,  were  compared  with  the  results  from  no  treatment,  Zavitz 
reported  yields  of  186,  189,  191,  and  179  bushels  per  acre,  respectively. 
Land  plaster  has  been  most  commonly  used  as  dust  because  of  its  cheapness 
and  its  adhesive  qualities.  On  the  basis  of  all  the  comparative  tests 
reported,  it  has  proved  the  most  efficient.  Sulfur  and  air-slaked  lime  have 
been  used  to  a  lesser  extent.  The  degree  to  which  dusting  was  practiced 
in  the  surveyed  regions,  as  related  to  the  length  of  time  the  cut  seed  was 
stored,  is  shown  in  table  52,  and  the  extent  to  which  various  dust  materials 
were  used  is  shown  in  table  53.  Unfortunately,  the  material  used  for 

TABLE  52.    RELATION  OF  DUSTING  TO  LENGTH  OF  STORAGE  PERIOD  OF  CUT  SEED  IN  THE 

FOUR  REGIONS  SURVEYED 


Franklin 

Long 

Steuben 

Monroe 

and 

.   •*       : 

Island, 

County, 

County, 

Clinton 

, 

1912 

1912 

1913 

Counties, 

1913 

Average  number  of  days  seed  was 

stored                                         .... 

5.7 

2.0 

2.2 

2  G 

Per  cent  of  growers  dusting  cut  seed 

57 

14 

17 

6 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1215 

TABLE  53.     PER  CENT  OF  GROWERS  DUSTING  SEED  WHO  USED  EACH  MATERIAL 


Franklin 

Long 

Steuben 

Monroe 

and 

Material 

Island, 

County, 

County, 

Clinton 

1912 

-   1912 

1913 

Counties, 

1913 

Land  plaster  

49    • 

72 

20 

11 

Sulfur  

43 

4 

16 

6 

Hydrated  lime  

1 

2 

0 

6 

Air-slaked  lime  

0 

0 

0 

67 

Road  dust  f  

0 

0 

6 

0 

Ashes  

3 

0 

2 

0 

Unnamed 

4 

22 

56 

10 

dusting  was  not  ascertained  from  all  the  growers  who  followed  this  practice. 
In  the  cases  in  which  it  was  not  ascertained,  it  was  listed  as  Unnamed. 
Land  plaster  was  shown  to  be  the  material  most  commonly  used,  with 
sulfur  second.  About  two- thirds  of  the  growers  in  Franklin  and  Clinton 
Counties  who  dusted,  used  air-slaked  lime,  which  was  not  used  in  any 
other  region.  Evidently,  because  of  the  likelihood  that  they  cause  scab, 
neither  form  of  lime  has  been  popular,  nor  have  wood  ashes. 


TYPE    OF    SEED 


Probably  no  other  phases  of  potato  culture  have  received  more  experi- 
mental attention  than  those  bearing  on  the  relation  of  type  and  amount 
of  seed  planted,  to  yield.  In  attempting  to  correlate  type  of  seed  with 
yield,  however,  the  all-important  factor  of  amount  of  seed  used  has  too 
often  been  neglected,  both  in  the  method  of  experimentation  and  in  the 
conclusions.  This  has  led  to  confusion,  false  conclusions,  and  a  con- 
glomeration of  published  data  of  questionable  value.  To  be  of  real  value, 
such  tests  must  take  into  account  both  the  types  of  seed  used  and  the 
amount  of  each  planted.  The  relation  of  type  of  seed  to  yield  may  be 
treated  under  the  following  headings:  (1)  large  as  compared  with  small 
tubers  for  seed,  (2)  whole  as  compared  with  cut  seed,  (3)  large  as  compared 
with  small  seed  pieces,  and  (4)  number  of  eyes.  In  reviewing  the  litera: 
ture  on  each  of  these  points,  it  has  been  difficult  to  reach  conclusions, 
because  of  the  confusion,  inmost  cases,  of  one  factor  with  one  or  more  of 
the  others;  and  very  often  the  amount  of  seed  planted  has  been  entirely 
neglected. 

Large  as  compared  with  small  tubers  for  seed 

More  than  thirty  years  ago,  Adams  (1889)  compared  the  yields  from 
large,  medium,  and  small  whole  seed,  and  found  an  increase  both  in  total 
and  in  marketable  yield  with  each  increase  in  size  of  tubers  used.  *  With  an 


1216  EARLE  V.  HARDENBURG 

equidistant  spacing  of  38  inches  for  each  type  of  seed,  more  per  acre  of 
the  large  than  of  the  small  type  was  planted.  Aicher  (1917)  compared 
the  yields  from  three  lots  of  whole  seed  of  a  given  variety  having  an  average 
tuber  weight  of  8,  4,  and  3  ounces,  respectively.  Tho  Aicher  did  not  state 
the  amount  of  seed  per  acre  used  for  each  lot  planted,  the  sets  of  each  lot 
were  planted  16  inches  apart  in  rows  3  feet  apart.  Aicher  reported  that 
as  the  size  of  the  whole  seed  was  increased,  the  number  of  stalks  per  hill 
and  the  total  yield  per  acre  were  increased.  There  was  little  difference 
in  the  percentage  of  marketable  yield  between  the  three  lots.  It  must  be 
concluded  from  this  that  large  whole  seed  is  better  than  small  whole  seed, 
under  equidistance  of  planting,  only  because  of  the  greater  weight  of  seed 
used.  Welch  (1917),  in  a  similar  experiment  and  under  similar  conditions, 
duplicated  Aicher's  results  almost  exactly,  except  that  he  obtained  a 
decrease  in  the  percentage  of  marketable  yield  as  the  size  of  the  whole 
seed  increased.  It  is  clear  that  the  greater  yields  obtained  by  Welch 
from  the  larger  whole  seed  were  due  primarily  to  the  almost  doubled  amount 
of  seed  involved  in  each  increase  in  size  of  seed  used.  Harwood  and  Holden 
(1893)  have  brought  together  the  results  obtained  at  the  New  York, 
Maryland,  Tennessee,  Kentucky,  Louisiana,  Wisconsin,  and  Utah  stations, 
in  all  of  which  it  was  shown  that  in  many  cases  not  only  the  gross  but  also 
the  net  yield  was  greatest  from  the  largest  whole  seed  tubers.  However, 
in  all  cases  this  increased  yield  was  obtained  from  the  greatly  increased 
amount  of  seed  used.  Zavitz  (1916)  selected  continuously,  for  eleven 
years,  seed  of  small  unmarketable,  small  marketable,  medium  marketable, 
and  large  marketable,  whole  seed  tubers,  and  planted  each  lot  in  duplicate 
plots.  With  but  one  slight  exception  in  the  eleven  years,  his  average 
marketable  yield  from  the  four  types  of  seed  showed  an  increase  with  each 
increase  in  size  of  seed  used.  The  average  yields  per  acre  from  the 
smallest  to  the  largest  seed,  for  the  eleven  years,  were  105,  145,  181,  and 
203  bushels,  respectively.  Zavitz  credits  these  differences  in  yield  to  the 
difference  in  the  weight  of  the  seed  tubers,  that  is,  to  the  difference  in  the 
amount  of  seed  planted  per  acre.  Plumb  (1890)  planted  whole  seed  of 
Early  Rose  varying  in  tuber  weight  from  14  ounces  down  to  1  ounce,  and 
concluded  from  his  results  that  the  larger  the  seed  tuber,  the  greater  was 
the  total  yield,  the  earlier  the  bloom,  the  taller  the  plant,  and  the  later  the 
maturity.  Plumb  obtained  a  consistent  decrease  in  net  yield,  however,  as 
the  size  of  the  seed  tuber  increased.  He  failed  to  duplicate  his  test  plots. 

Whole  as  compared  with  cut  seed 

The  advisability  of  cutting  seed  potatoes  depends  on  three  factors: 
the  cost  of  labor,  the  cost  of  seed,  and  the  relative  merit  of  whole  as  com- 
pared with  cut  seed  in  the  effect  on  yield.  Literature  reporting  experi- 
mental data  on  this  question  considers  only  the  last-named  factor.  Gutting 
seed  tubers  at  once  facilitates  loss  of  sap  by  bleeding,  and  the  entrance  of 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1217 

rot-producing  bacteria  and  fungi.  Appleman  (1918)  has  shown  that  the 
transverse  cutting  of  seed  tubers  permits  development  in  the  median  and 
basal  eyes  which  would  remain  more  or  less  dormant  if  the  tubers  were 
planted  whole,  due  to  the  exclusive  development  of  the  terminal  eyes. 
This  would  indicate  a  more  economical  use  of  seed  than  is  the  case  if 
whole  tubers  are  planted.  Aicher  (1917)  and  Welch  (1917),  in  a  three- 
years  duplicate  experiment  on  irrigated  land  in  Idaho,  compared  whole  and 
cut  seed  as  to  stand,  earliness,  and  yield.  Aicher  obtained  an  earlier 
growth,  a  more  prolific  top  growth,  a  larger  total  yield,  and  a  smaller 
marketable  yield,  from  whole  than  from  cut  tubers.  Welch  obtained  a 
better  stand  from  the  whole  tubers,  but  one  that  was  not  commensurate 
with  the  extra  amount  of  seed  required.  He  also  obtained  a  smaller 
marketable  yield  from  whole  than  from  cut  tubers,  but  he  does  not  agree 
with  Aicher  that  wholeness  has  anything  to  do  with  earliness.  The 
writer  is  of  the  conviction  that,  so  far  as  the  relative  merit  of  whole  and  of 
cut  seed  is  concerned,  these  tests  of  Aicher  and  Welch  are  no  true  criterion. 
The  much  greater  rate  of  planting  of  whole  seed  over  cut  seed  invalidates 
any  conclusion  that  may  be  drawn  relative  to  differences  in  yield.  Har- 
wood  and  Holden  (1893)  reported  an  interesting  experiment  attempted 
by  the  Tennessee  station  to  test  the  comparative  yields  from  whole  tubers 
and  from  an  equal  weight  of  halved  tubers  from  the  same  lot  of  seed. 
This  eliminated  any  possible  difference  in  rate  of  planting,  so  far  as  total 
weight  of  seed  was  concerned,  but  the  fact  that  the  half  tubers  were 
planted  on  twice  as  much  area  as  the  whole  tubers  vitiated  the  object  of 
the  experiment.  Nearly  two  and  a  half  times  as  much  merchantable 
yield  was  obtained  from  the  half  tubers  as  from  the  whole.  These  same 
authors  report  a  more  nearly  accurate  test  made  by  the  New  York  station, 
in  which  equal-weight  seed  pieces  of  whole  and  cut  types  were  used.  The 
average  total  yield  per  acre  was  the  same  from  the  whole  and  the  cut  seed, 
but  the  marketable  yield  per  acre  from  the  cut  seed  was  nearly  double  that 
from  the  whole  seed. 

Large  as  compared  with  small  seed  pieces 

The  question  of  size  of  the  seed  piece  in  relation  to  yield  has  been  treated 
experimentally  on  the  basis  of  both  weight  and  proportion  of  tuber. 
Neither  basis  can  be  considered  quite  separately,  and  both  naturally 
involve  the  question  of  rate  of  planting,  the  spacing  of  the  seed  remaining 
constant.  The  hundreds  of  experiments  recorded  for  the  study  of  size 
of  seed  piece  are  virtually  tests  of  the  most  efficient  rate  of  planting,  tho 
the  objects  of  and  the  conclusions  for  them  have  been  related  to  size  of 
piece  alone. 

Plumb  (1890),  comparing  the  yields  from  whole  tubers,  halves,  quarters, 
and  single-eye  pieces,  obtained  an  increased  yield  with  every  increase  in  size 
of  seed,  tho  the  greatest  merchantable  yield  was  obtained  with  the  half 


1218  EARLE  V.  HARDENBURG 

tuber.  As  early  as  1886,  Samuel  Johnson  (1886)  compared  the  yields 
from  whole  and  half  tubers  and  from  three-,  two-,  and  one-eye  pieces,  and 
found  that,  whereas  the  whole  tuber  gave  the  highest  total  yield,  the 
three-eye  piece  gave  the  highest  marketable  yield.  Two  years  later, 
comparing  the  same  types  of  seed,  Johnson  (1888)  obtained  a  consistent 
gain  in  yield  with  each  increase  in  size  of  seed,  and  a  decrease  in  percentage 
of  stand  with  each  decrease  in  size  of  seed.  Johnson  did  not  report 
whether  his  highest  total  yields  were  also  the  highest  net  yields. 

Taft  (1892),  in  a  three-years  test,  compared  the  efficiency  of  various 
rates  of  planting,  by  planting  whole,  half,  quarter,  and  eighth  tubers, 
and  single-eye  pieces,  equidistant  in  the  row.  His  net  yields  increased 
up  to  and  including  the  half  tuber,  altho  the  highest  total  yield  came  from 
whole  seed.  Adams  (1889),  using  whole,  half,  two-eye,  and  one-eye  seed 
pieces,  obtained  an  increased  total  yield  up  to  and  including  whole  seed, 
with  the  greatest  marketable  yield  from  two-eye  pieces.  He  did  not  report 
in  terms  of  net  yield.  Green  (1887)  reported  a  two-years  average  test  of 
the  yields  from  one-eye,  two-eye,  half,  and  whole  seed  pieces  as  increasing 
with  the  size  of  piece  used,  but  made  no  mention  of  the  net  or  the  market- 
able yields  or  of  the  rate  of  planting.  Hutcheson  and  Wolfe  (1917)  made  a 
three-years  comparison  of  the  yields  from  single-eye,  half -ounce,  one- 
ounce,  and  two-ounce  pieces.  Whereas  both  total  and  marketable  yield 
increased  up  to  and  including  the  two-ounce  piece,  the  increased  yield 
from  the  two-ounce  over  that  from  the  one-ounce  piece  was  not  sufficient 
to  warrant  the  use  of  pieces  larger  than  one  ounce  in  weight.  Aicher 
(1917)  and  Welch  (1917),  in  their  duplicate  experiment  covering  three 
years,  concurred  in  the  results  showing  the  highest  total  yield  to  be  from 
whole  seed  and  the  highest  marketable  yield  from  quartered  seed  pieces, 
in  a  comparison  of  whole,  halved,  and  quartered  seed  pieces.  These 
investigators  were  agreed  also  that  the  number  of  stalks  per  hill  increased 
with  the  size  of  piece  planted,  a  fact  which  probably  accounts  for  the  smaller 
percentage  of  marketable  tubers  from  the  largest  seed. 

Appleman  (1918)  tested  the  influence  of  weight  of  seed  piece  on  yield 
by  varying  the  weight  from  0.08  to  1.75  ounces  in  the  variety  McCormick 
and  from  0.61  to  1.46  ounces  in  the  variety  Irish  Cobbler.  To  give  due 
consideration  to  rate  of  planting  in  such  a  test,  he  showed  how  this  vari- 
ation in  McCormick  increased  the  amount  of  seed  from  1.1  to  24.96 
bushels  per  acre.  He  obtained,  in  both  varieties,  an  increased  total  yield 
with  each  increase  in  weight  of  the  seed  piece. 

Zavitz  (1916)  has  furnished  perhaps  the  best  contribution  to  the  study 
of  this  factor.  In  ten  tests,  covering  five  years,  he  compared  one-sixteenth-, 
one-eighth-,  one-quarter-,  one-half-,  one-,  and  two-ounce  seed  pieces,  the 
rate  of  planting  varying  from  1.3  to  41.2  bushels  per  acre  and  the  number  of 
eyes  in  each  set  remaining  constant.  With  no  seed  piece  weighing  more 
than  two  ounces,  Zavitz  found  increased  net,  marketable,  and  total 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1219 

yields  for  each  increase  in  size  of  seed  pieces  used.  But  here  he  also  failed 
to  consider  the  factor  of  rate  of  planting.  In  another  five-years  experi- 
ment, however,  testing  the  efficiency  of  various  spacings  of  seed,  he  has, 
apparently  unconsciously,  furnished  some  much-needed  information.  This 
test  showed  that  with  the  same  weight  of  seed  planted  per  acre,  the  one- 
ounce  sets,  planted  twice  as  close  as  the  two-ounce  sets,  gave  greater 
total,  marketable,  and  net  yields. 

Hume,  Champlin,  and  Oakland  (1914)  compared  large,  medium,  and 
small  seed  pieces,  eye  frequency  being  constant,  and  observed  an  average 
increase  of  total  yield,  in  two  varieties,. of  70.9  per  cent  in  large  seed  pieces 
and  55.5  per  cent  in  medium  seed  pieces,  over  that  from  the  small  seed 
pieces.  Emerson  (1907)  conducted  a  very  comprehensive  and  accurate 
test  of  the  relation  of  size  of  seed  piece  to  yield  under  a  constant  rate  of 
planting.  Planting  eighth,  quarter,  and  half  tubers,  6,  12,  and  24  inches 
apart,  respectively,  he  used  18  bushels  of  seed  per  acre  in  each  plot.  This 
gave  him  the  highest  total  yield  per  acre  from  the  quarter-tuber  pieces 
and  the  lowest  total  yield  from  the  half  tubers.  This,  together  with  the 
test  by  Zavitz  (1916)  previously  cited,  would  indicate  that  with  the  same 
rate  of  planting  per  acre,  smaller  pieces,  down  to  one  ounce,  planted  closer, 
are  likely  to  give  larger  yields  than  larger  pieces  planted  farther  apart. 

Schweitzer  (1896),  with  twelve  varieties  in  a  one-year  test,  compared 
the  total  yields  and  the  yields  of  small  tubers  from  one-eye,  two-eye, 
quarter-tuber,  half- tuber,  and  whole-tuber  pieces.  This  gave  a  variation 
in  rate  of  planting  of  from  4  to  87  bushels.  His  total  yield  increased  with 
each  increase  in  size  of  seed  piece  and  in  rate  of  planting.  Also,  the  per- 
centage of  small  potatoes  increased  from  8.9  for  one-eye  pieces  to  26.4 
for  whole  tubers  as  seed. 

Harwood  and  Holden  (1893)  brought  together  a  compilation  of  experi- 
ments from  thirteen  stations  designed  to  test  the  relation  of  size  of  seed 
and  rate,  of  planting,  to  yield.  In  summarizing  the  comparative  value  of 
whole  and  of  half  tubers  as  seed,  they  showed  that  the  results  of  a  sub- 
stantial majoritjr  of  these  experiments  were  in  favor  of  the  whole  tuber, 
not  only  for  total  and  marketable  yield,  but  also  for  net  marketable 
yield  and  net  value  of  the  crop.  Similarly,  a  majority  of  the  compari- 
sons of  the  half-tuber  and  the  two-eye  piece  favored  the  former  thruout. 
In  drawing  such  conclusions,  it  must  be  borne  in  mind  that  these  dif- 
ferences in  yield  were  due  to  an  increase  in  the  amount  of  seed  used 
because  of  the  larger  size  of  the  seed  piece.  These  authors  called  at- 
tention to  the  conclusions  of  the  Ohio  station,  that  "  despite  the  fact 
that  whole  potatoes  give  more  small  potatoes  than  one  and  two  eye  cut- 
tings, it  is  also  true  that  they  give  more  large  potatoes." 

The  foregoing  review  of  the  question  of  large  as  compared  with  small 
seed  shows  that  few  tests  have  actually  proved  any  superior  merit  of  large 
seed,  except  as  the  amount  used  per  acre  was  increased.  The  few  tests  of 


1220  EARLE  V.  HARDENBURG 

a  more  comprehensive  nature  have  indicated  that  equivalent  amounts  of 
smaller  seed  pieces,  down  to  a  minimum  weight  of  one  ounce,  planted 
closer,  may  give  even  more  efficient  results.  With  an  expensive  and 
limited  seed  supply,  the  latter  type  of  seed  and  system  of  planting  would 
seem  advisable. 

Number  of  eyes 

Many  of  the  older  potato  growers  attach  considerable  importance  to 
the  number  of  eyes  to  be  left,  in  cutting  seed  potatoes.  While  a  few 
growers  cut  single-eye  pieces,  the  majority  prefer  pieces  containing  two  eyes. 
Whether  or  not  there  is  any  significance  in  the  relation  of  this  factor  to 
yield  or  to  quality  of  the  crop,  it  is  automatically  controlled,  in  practice, 
by  the  size  of  the  seed  piece,  the  importance  of  which  has  already  been 
discussed.  Arthur  (1892)  showed,  in  very  definite  terms,  that  the  yield  of 
large  tubers  decreases  with  the  use  of  seed  tubers  weighing  more  than 
four  and  one-half  ounces.  His  results  are  in  accord  with  those  of  many 
other  experiments  which  show  that  increasing  the  number  of  eyes  on  the 
seed  piece  tends  to  reduce  the  average  size  of  the  resulting  tubers. 

Whipple  (1915)  studied  the  influence  of  thinning  to  one  stalk  per  hill, 
in  a  two-years  test  of  nine  varieties  planted  from  two-ounce  pieces  irre- 
spective of  the  number  of  eyes.  Thinning  to  one  sprout  improved  the 
market  shape  and  the  uniformity  of  the  crop,  but  Whipple's  results  do 
not  justify  any  conclusion  that  either  total  or  marketable  yield  was 
increased  by  thinning.  The  cost  of  thinning  was  therefore  not  warranted. 

Ballou  (1910)  has  shown  that  varieties  differ  in  the  number  of  stalks  per 
hill  which  will  develop  from  a  given  size  of  seed  piece.  Bovee,  having 
frequent  eyes,  developed  more  stalks  per  hill  per  unit  of  seed  piece  than 
did  Carman  No.  3,  a  variety  of  few  eyes.  Ballou  obtained  an  increase 
in  the  unmarketable  yield  from  every  increase  in  size  of  seed  piece  or 
number  of  eyes  in  both  varieties.  The  most  profitable  net  yield  in  the 
Bovee  was  obtained  from  two-eye  pieces  planted  at  the  rate  of  15  bushels 
per  acre,  and  in  the  Carman  No.  3  from  half-tuber  pieces  planted  at  the 
rate  of  25  bushels  per  acre. 

Again  it  remained  for  Zavitz  (1916)  to  contribute  the  real  test  of  the 
influence  of  eye  frequency  on  yield,  by  eliminating  the  factor  of  size  of 
seed  piece.  Using  one-ounce  seed  pieces  thruout  a  five-years  test,  he 
compared  the  results  from  seed  pieces  containing  one,  two,  three,  four, 
and  five  eyes,  respectively,  and  found  that  as  the  number  of  eyes  increased, 
the  average  total  yield  increased  and  the  percentage  of  marketable  yield 
decreased.  The  difference  in  marketable  yield,  however,  was  in  no  case 
more  than  5  per  cent.  It  is  therefore  evident  from  Zavitz 's  work  that 
the  yield  is  proportional  to  the  number  of  stalks  per  hill,  as  well  as  to  the 
size  of  the  seed  piece,  and  that  nothing  is  to  be  gained  by  cutting  to  a 
certain  minimum  number  in  preparing  seed  for  planting. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1221 

Types  of  seed  used  in  the  four  regions  surveyed 

Obviously  there  are  many  difficulties  in  the  way  of  attempting  to  deter- 
mine by  survey  methods  the  relation  of  type  of  seed  to  yield.  Whether 
or  not  a  grower  decides  to  cut  his  seed  rather  than  plant  it  whole,  depends 
principally  on  the  size  of  the  tubers  he  has  for  seed,  because,  in  cutting 
for  seed,  most  growers  have  a  definite  size  of  seed  piece  in  mind.  Growers 
in  Steuben  County,  more  than  in  other  regions,  showed  a  tendency  to 
plant  seed  of  low  market  value.  Much  cull  seed  was  therefore  planted 
whole  in  1912.  Since  practically  all  seed  used  on  Long  Island  is  bought 
and  is  of  a  grade  higher  than  the  average,  growers  there  find  it  economical 
to  cut  nearly  all  of  it.  Good  seed  is  more  cheaply  produced  and  more 
plentiful  in  Franklin  and  Clinton  Counties,  and  therefore  relatively  large 
seed  is  used  there,  and  more  of  it  is  planted  whole  than  in  the  other  regions. 
The  proportion  of  whole  and  of  cut  seed  used  in  the  four  surveyed  regions 
is  shown  in  table  54: 

TABLE  54.     PER  CENT  OF  GROWERS  USING  WHOLE  AND  CUT  SEED,  IN  THE  FOUR  REGIONS 

SURVEYED 


Franklin 

Long 

Steuben 

Monroe 

and 

Type  of  seed 

Island, 

County, 

County, 

Clinton 

1912 

1912 

1913 

Counties, 

1913 

Whole  

0 

1 

0 

10 

Whole  and  cut 

0 

40 

26 

39 

Cut 

100 

59 

74 

51 

Evidently  there  are  very  few  growers  who  feel  that  their  seed  is  small 
enough,  cheap  enough,  or  low  enough  in  quality  to  warrant  planting  it 
whole.  However,  it  is  not  possible  to  judge  from  table  54,  by  the  amount 
of  each  type  of  seed  used,  which  region  used  the  best  seed  in  the  year  for 
which  the  data  were  taken.  It  has  not  been  possible  to  study  the  influence 
of  the  size  of  seed  piece  on  yield,  in  these  regions,  because  of  the  impossi- 
bility of  determining  even  the  average  size  of  the  seed  used.  In  studying 
the  influence  of  the  size  or  the  degree  of  wholeness  of  the  tubers  used  for 
seed,  definite  conclusions  cannot  be  drawn  because  of  the  lack  of  uniformity 
in  the  opinions  of  the  growers  as  to  the  meaning  of  the  terms  large,  medium, 
and  small,  and  furthermore  because  in  many  cases  more  than  one  type  of 
seed  was  used.  The  data  are  presented  here  for  whatever  significance  they 
may  have. 

On  Long  Island,  as  Already  stated,  all  the  seed  used  in  1912  was  cut. 
A  comparison  of  the  yields  from  large  tubers  cut  and  from  medium-sized 
tubers  cut,  is  given  in  table  55.  The  difference  of  8.6  bushels  per  acre  in 


1222 


EARLE  V.  HARDENBURG 


TABLE  55.     RELATION  OF  TYPE  OF  SEED  TO  YIELD  ON  171  LONG  ISLAND  FARMS  IN  1912 


Type  of  seed 

Number 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value 
of  manure 
and 
fertilizer 

Large  cut 

99 

163  1 

12  0 

$31  24 

Medium-»sized  cut  ... 

72 

171  7 

13  0 

33  18 

Total  

171 

Average.  .... 

• 

167  0 

12  4 

$31  48 

favor  of  the  medium-sized  tubers  cut  is  no  more,  and  is  probably  less, 
than  should  be  expected  from  the  increased  amount  of  seed  and  fertilizer 
used  by  this  group  of  growers.  Apparently  there  was  little  choice  between 
the  two  sizes  of  tubers  used. 

The  practice  of  cutting  seed  of  egg  size  for  planting  was  probably  com- 
moner in  Steuben  County  than  in  the  other  regions.  Some  whole  seed 
which  might  be  classed  as  cull  was  also  used  by  some  of  the  less  progressive 
growers,  as  shown  in  table  56.  The  yields  given  in  table  56  correlate 

TABLE  56.     RELATION    OF    TYPE    OF    SEED    TO    YIELD    ON    217     STEUBEN    COUNTY 

FARMS  IN  1912 


Type  of  seed 

Num- 
ber of 

farms 

Average 
yield 
per  acre 

(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Large  and  medium-sized  cut  
Large  cut  

98 
11 

149.7 
139.1 

9.9 
10.1 

$10.94 
12.70 

Medium-sized  cut  

102 

135.7 

10.3 

10.83 

Small  whole 

4 

95  5 

9  4 

6  84 

Medium-sized  whole  

2 

181.1 

11.5 

9.53 

Total 

217 

Average 

146  5 

10.4 

$10.89 

rather  closely  with  the  rate  of  planting  and  the  value  of  manure  and  ferti- 
lizer used.  The  four  growers  who  used  small  whole  seed  also  used  the 
least  seed  and  fertilizer,  and,  as  a  result,  harvested  the  lowest  average 
yield.  In  view  of  the  amount  of  seed  and  fertilizer  used,  the  growers 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1223 


who  used  a  combination  of  both  large  and  medium-sized  cut  seed  obtained 
a  more  profitable  net  yield  than  did  those  who  used  either  large  or  medium- 
sized  cut  seed  alone. 

So  far  as  is  possible  from  the  data  taken,  the  relation  of  type  of  seed  to 
yield  in  Monroe  County  is  shown  in  table  57.     More  than  a  third  of  the 

TABLE  57.    RELATION    OF    TYPE    OF    SEED    TO    YIELD    ON    257    MONROE    COUNTY 

FARMS  IN  1913 


Type  of  seed 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Medium-sized  cut  

120 

143.5 

12.0 

$11.75 

Medium-sized  whole  and  large  cut  
Small  whole  and  medium-sized  cut  
Large  cut  

18 
30 
52 

132.5 
132.1 
131.5 

12.8 
12.8 
13.1 

13.26 
9.56 
12.56 

Large  and  medium-sized  cut  
Small  whole  and  large  cut  
Medium-sized  whole  and  medium-sized 
cut  .                      

17 
2 

18 

129.5 
122.9 

120.5 

12.3 
11.0 

11.4 

12.66   , 
12.28 

9.11 

Total  

257 

Average                 .  .                     

136.2 

12  3 

$11.63 

growers  in  this  region  used  medium-sized  cut  seed  in  1913.  Judging  from 
the  average  amount  of  seed  and  fertilizer  used  by  these  same  growers, 
they  obtained  a  more  profitable  net  yield  than  did  the  growers  who  used 
either  large  cut  seed  or  large  and  medium-sized  cut  seed.  The  real  expla- 
nation as  to  why  the  group  using  medium-sized  whole  and  medium-sized 
cut  seed  obtained  the  lowest  average  yield,  lies  in  the  fact  that  these  growers 
used  considerably  less  than  the  average  amount  of  seed  and  fertilizer. 

Except  that  more  whole  seed  was  used  in  Franklin  and  Clinton  Counties, 
the  types  of  seed  used  there  correspond  fairly  closely  to  those  reported  for 
Monroe  County.  The  fact  that  about  a  third  of  the  growers  in  this 
region  claimed  to  have  used  large  cut  seed  indicates  that  these  growers 
use  seed  of  larger  average  size  than  is  used  in  any  of  the  other  regions. 
The  relation  of  type  of  seed  to  yield  here  is  shown  in  table  58.  The  com- 
parative yields  from  large  cut  and  medium-sized  cut  seed  agree  very  well 
with  the  majority  of  the  experiments  previously  cited,  which  showed 
greater  yields  from  the  larger  seed,  due  to  the  greater  amount  of  seed 
planted.  The  difference  of-  about  8  bushels  per  acre  of  average  yield 
between  medium-sized  cut  and  medium-sized  whole  seed,  however,  does 


1224 


EARLE  V.  HARDENBURG 


TABLE  58.     RELATION  OF  TYPE  OF  SEED  TO  YIELD  ON  292  FRANKLIN  AND  CLINTON  COUNTY 

FARMS  IN  1913 


Type  of  seed 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Large  cut  

97 

189.1 

12  9 

$13  61 

Medium-sized  whole  and  large  cut  
Medium-sized  whole  an  .  medium-sized 
cut 

64 
21 

182.7 
181  5 

'  12.4 
11  8 

12-.CO 
10  49 

Medium-sized  cut  ... 

42 

174  6 

11  1 

12  91 

Medium-sized  whole  .... 

32 

166  7 

11  0 

13  02 

Medium-s'zed  and  large  cut  

8 

166.1 

12  0 

14  08 

Small  whole  and  large  cut  

6 

157.8 

11  1 

15  81 

Small  whole  and  medium-azed  cut  

22 

157.3 

9.9 

12.01 

Total  

292 

Average 

178  5 

11  9 

$12  96 

not  agree  with  the  experiments  previously  cited  for  the  factor  of  whole  as 
compared  with  cut  seed.  The  apparent  discrepancy  cannot  be  attributed 
to  differences  in  amount  of  seed  and  in  value  of  manure  and  fertilizer,  as 
these  factors  average  approximately  the  same  for  both  groups. 

A  rather  striking  effect  of  the  rate  of  planting  is  shown  in  table  58, 
where  the  types  of  seed  are  arranged  according  to  the  average  yields 
obtained  from  each.  In  fact,  thruout  these  studies  of  the  relation  of  type 
of  seed  to  yield,  it  has  been  shown  that  those  types  which  required  the 
highest  rate  of  planting  were  productive  of  the  highest  average  yields. 


RELATION    OF   AMOUNT    OF    SEED    TO    YIELD 

The  very  marked  effect  of  rate  of  planting  on  yield  has  been  shown  in  the 
previous  discussions  of  the  effect  of  manure  and  fertilizer  and  of  size  of 
seed  piece.  A  majority  of  the  very  large  number  of  tests  which  have  been 
conducted  to  determine  the  optimum  number  of  bushels  per  acre  to  plant, 
indicate  that  in  this  country  too  little  seed  is  generally  planted,  under 
average  conditions.  In  contrast  to  this,  the  large  yields  obtained  by 
European  growers,  who  commonly  plant  from  30  to  40  bushels  of  seed  per 
acre,  are  often  cited.  It  does  not  follow,  however,  that  similar  rates  of_ 
planting  in  New  York  would  be  productive  of  such  yields.  Land,  labor, 
and  climatic  conditions  in  northern  Europe  are  such  that  high  rates  of 
planting  are  not  only  possible  but  also  profitable.  As  shown  by  the  major- 
ity of  experiments  testing  this  factor,  the  most  profitable  rate  of  planting 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1225 

has  seldom  been  exceeded  in  this  country.  Rate  of  planting  is  increased 
either  by  closer  planting  or  by  increasing  the  size  of  the  seed  piece. 

Harwood  and  Holden  (1893)  compiled  the  results  of  thirteen  experiments 
conducted  at  the  Michigan  station  to  determine  the  optimum  rate  of 
planting  as  well  as  the  optimum  size  of  seed  piece.  The  rates  of  planting 
varied  from  2.7  to  58.9  bushels  per  acre.  The  net  yields  showed  that  the 
optimum  rates  of  planting  varied  from  10.8  to  48  bushels  per  acre.  In 
only  four  tests  was  the  best  rate  of  planting  higher  than  24  bushels. 
Emerson  (1907)  tested  rates  of  planting  varying  from  6  to  36  bushels  per 
acre  when  eighth,  quarter,  and  half  tubers  were  used.  He  found  that  12, 
18,  and  36  bushels  per  acre  were  the  best  amounts  to  use  for  these  respective 
sizes  of  seed  pieces.  Macoun  (1905),  by  varying  the  spacing  of  the  seed 
from  10  to  18  inches  and  thereby  varying  the  rate  of  planting  from  35  to 
19  bushels  per  acre,  obtained  the  highest  net  yield  from  25  bushels  of  seed. 
Kohler  (1910),  using  the  varieties  Early  Ohio  and  Sir  Walter  Raleigh, 
varied  the  rate  of  planting  in  each  by  3  and  by  2J  bushels,  respectively, 
from  6  to  21  bushels  in  the  Early  Ohio  and  from  5  to  20  bushels  in  the  Sir 
Walter  Raleigh.  He  obtained  the  highest  marketable  yield  in  the  Early 
Ohio  from  12  bushels  of  seed,  and  in  the  Sir  Walter  Raleigh  from  17.5 
bushels. 

Zavitz  (1916),  using  only  one-eye  pieces,  varied  the  rate  of  planting 
from  1.3  to  41.2  bushels  by  increasing  the  size  of  the  seed  piece.  Here 
both  the  highest  net  yield  and  the  highest  marketable  yield  were  obtained 
from  using  41.2  bushels  of  seed.  Zavitz's  test  covered  a  five-years  period, 
and  is  therefore  more  significant  in  this  respect  than  the  other  tests  just 
reported. 

The  wide  variation  in  the  optimum  rate  of  planting  shown  by  the 
experiments  here  reported,  indicates  that  the  available  soil  moisture  and 
the  fertility  have  much  influence  in  limiting  the  stand  of  plants  which 
will  develop  to  maximum  productivity.  In  other  words,  the  potato  soils 
of  Steuben  County,  which  are  naturally  low  in  fertility,  cannot  be  expected 
to  produce  the  average  yields  that  are  obtained  in  Monroe,  Franklin,  and 
Clinton  Counties.  From  a  review  of  the  data  available  up  to  this  time, 
it  seems  a  safe  assumption  that,  under  at  least  average  conditions,  the  rate 
of  planting  may  be  profitably  increased  from  its  present  average  to  from  15 
to  18  bushels  per  acre.  Where  weed  control  is  important,  labor  scarce 
and  expensive,  and  land  relatively  cheap,  checkrowing  is  a  common 
system  of  planting.  Tho  this  system  naturally  lowers  both  the  rate  of 
planting  and  the  resulting  yield,  both  may  be  increased  by  increasing  the 
size  of  seed  piece  used. 

Rate  of  planting  on  Long  Island 

In  spite  of  the  fact  that  the  growers  on  Long  Island  pay  relatively  high 
prices  for  nearly  all  of  their  seed  every  year,  they  have  apparently  learned 


1226 


EARLE  V.  HARDENBURG 


that  it  is  not  profitable  to  plant  less  than  the  average  of  12.5  bushels  per 
acre.  The  influence  of  the  rate  of  planting  on  the  yield  for  this  region 
in  1912  is  shown  in  table  59.  It  may  be  seen  in  this  table  that  there  was 


TABLE  59.     RELATION 


RATE  OF  PLANTING  TO  YIELD  ON  330  LONG  ISLAND  FARMS  IN 
1912 


Rate  of  planting 
(bushels  per  acre) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Less  than  11  

71 

148.9 

9.9 

$28.79 

11-12  

68 

181.4 

11.3 

32.34 

12-13  

77 

161.7 

12.2 

31.50 

13-14  

49 

179.5 

13.4 

33.52 

14-15  

33 

193.0 

14.1 

33.06 

15  and  more 

32 

202  0 

15.6 

36.63 

Total 

330 

Average 

175.5 

12.5 

$32.40 

Yield  per  acre,  in  bushels 

i        i      1*       T       T       T       ^       ^       ^ 

CO           i—  I           CO              i—  i              CO              i—  i              CO              i—  ICO 
C^           >-O          t^»             CO             C^l             *O             t^»             CO             C^l 

»o         o 

<M             CO 

±            ci 
S            ^ 

301-325 

7 

1 

& 

8 

1 

1 

1 

1 

1 

§ 

9 

4 

3 

1 

1 

1 

1 

s, 

10 

2   8 

8 

15 

9 

7 

2 

1 

2 

p*N 

11 

2   3 

8 

20 

7 

11 

6 

6 

3 

1 

1 

1 

12 

2   6 

12 

23 

10 

11 

4 

4 

1 

3 

1 

02 

13 

2 

5 

12 

5 

11 

6 

4 

2 

1 

1 

*8 

14 

1       1 

4 

3 

13 

3 

6 

2 

CO 

~ 

15' 

2 

1 

2 

3 

5 

4 

1 

2 

1 

1 

1 

pq 

16 
17 

1 

3 

1 

1 

1 

1 

18 

1 

1 

1 

1 

5 

11 

54 

68 

77 

49 

33 

21 

5 

3 

3 


1    6   27   38   81    43   60   27   23    13    8    3   330 
r  =  0.273  ±  0.034 

FlG.    140.       CORRELATION    OF    RATE    OF    PLANTING   AND    YIELD    ON    330    LONG   ISLAND    FARMS 

IN   1912 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1227 


a  tendency  among  the  growers  who  planted  the  most  seed  to  use  also 
somewhat  more  than  the  average  value  of  manure  and  fertilizer.  Also, 
there  was  more  spraying  for  blight  among  these  growers.  However,  the 
same  marked  influence  on  the  yield  from  the  rate  of  planting  is  shown  in 
table  24,  under  the  discussion  of  manure  and  fertilizer,'  where  each  of  these 
factors  is  treated  under  the  various  subheads.  The  single  discrepancy  in 
table  59,  in  the  group  of  growers  using  from  11  to  12  bushels  of  seed,  is 
due,  at  least  in  part,  to  the  larger  value  of  manure  and  fertilizer  used  by 
this  group.  Since  the  average  number  of  eyes  per  piece  gradually  in- 
creased from  the  lowest  to  the  highest  rate  of  planting,  it  may  be  con- 
cluded that  the  rate  of  planting  varied  not  so  much  according  to  closeness 
of  planting  as  according  to  size  of  seed  pieces  used.  From  table  59,  it 
is  apparent  that  the  growers  in  this  region  who  used  as  high  as  15  bushels 
of  seed  per  acre  in  1912,  did  not  use  more  than  was  profitable.  Applying 
the  biometrical  measure  of  correlation  of  this  factor  with  yield  (fig.  140) 
shows  the  significant  coefficient  0.275  db  0.034. 

Rate  of  planting  in  Steuben  County 

In  the  four  regions  surveyed,  Steuben  County  growers  used  the  least 
seed,  planting  an  average  of  only  10.1  bushels  per  acre  in  1912  (table  60). 
The  highest  rate  reported  by  any  of  the  360  growers  was  18  bushels,  and 

TABLE  60.    RELATION  OF  RATE  OF  PLANTING  TO  YIELD  ON  360  STEUBEN  COUNTY  FARMS 

IN  1912 


Rate  of  planting 
(bushels  per  acre) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

6-  8.. 

19 

117  8 

6  9 

$  9  17 

8-10  

138 

12S  1 

8  6 

9  27 

10-12  

126 

138  3 

10  2 

10  17 

12-14  

57 

147  7 

12  5 

10  96 

14-18  

20 

191  3 

15  4 

12  63 

Total  

360 

Average  

136    L 

10  1 

$10  06 

there  was  a  profitable  increase  in  yield  from  every  increase  of  2  bushels 
per  acre  planted,  up  to  18  bushels.  Steuben  County  growers  did  not 
exceed  the  optimum  rate  of  planting  in  1912,  and  it  is  safe  to  recommend  a 
considerable  increase  in  the  average  amount  of  seed  used  in  that  region. 


.1228 


EARLE  V.  HARDENBURG 


Altho  the  increased  yields  were  due  partly  to  the  increased  values  of 
manure  and  fertilizer  used,  this  factor  has  been  studied  in  a  separate 
grouping  in  table  25  under  the  discussion  of  the  value  of  manure  and 
fertilizer  for  the  region.  The  low  average  rate  of  planting  for  this  county 
in  1912  was  due  partly  to  the  planting  of  a  considerable  area  in  check- 
rows and  partly  to  the  use  of  small  and  relatively  inferior  seed.  The  data 
show  that  the  amount  of  seed  used  probably  did  not  exceed  the  maximum 
which  the  relatively  low  soil  fertility  could  support.  The  coefficient  of 
correlation  between  rate  of  planting  and  yield  for  this  region,  0.374  db 
0.031  (fig.  141),  is  the  highest  found  for  any  of  the  four  regions. 


Yield  per  acre,  in  bushels 


3 


=3         g 

§3  9 
£  10 
8  11 

"  12 
o  13 

•S    14 

•S    15 

m     6 

17 

18 


-    £    s 

1 

T—  I 

O 
1—  1 

I 

i 

10 

c^ 

<N           <M        O1        CO        CO        CO        CO 

f^           CSJ        *O        t^*        <^        C^        to 
<N           <M        <M        <N        CO        CO        CO 

1 

1 

2 

2 

2 

1 

1 

8 

1                  2 

7 

4 

2 

4 

20 

2      11 

15 

23 

15 

8 

5 

1        2 

82 

1        3 

11 

13 

11 

7 

2 

51 

2        5 

18 

20 

25 

15 

15 

4        1 

105 

1 

2 

2 

6 

2 

4 

1 

18 

3 

5 

8 

7 

8' 

5 

1        2              1 

40 

7 

4 

1 

1 

13 

1 

1 

1 

2 

1 

1 

7 

3 

2 

1 

1        2                                    1 

10 

1 

1 

2 

1 

1 

1              1 

2 

2        5      26      64      73      78      52      38        9      10      0      2      0      0      1      360 
r  =  0.374  ±0.031 

FlG.   141.       CORBELATION   OF   BATE   OF   PLANTING  AND   YIELD   ON   360  STEUBEN  COUNTY  FARMS 

IN  1912 

Rate  of  planting  in  Monroe  County 

The  average  amount  of  seed  per  acre  used  in  Monroe  County  in  1913 
was  12.5  bushels,  which  was  the  same  average  as  was  used  on  Long  Island 
in  1912.  The  relation  of  this  factor  to  yield  is  shown  in  table  61.  Altho 
there  was  a  tendency  among  the  growers  who  planted  the  most  seed  to 
use  more  manure  and  fertilizer,  the  influence  of  seed  is  nearly  as  marked 
in  this  region  as  in  the  others.  A  few  growers  used  as  much  as  20  bushels 
or  more  per  acre,  and,  without  using  more  fertilizer  than  was  used  by 
growers  planting  from  14  to  16  bushels  per  acre,  they  obtained  an  average 
increase  in  yield  of  about  25  bushels  per  acre.  It  appears,  however,  that 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1229 


TABLE  61. 


RELATION  OF  RATE  OF  PLANTING  TO  YIELD  ON  300  MONROE  COUNTY  FARMS 
IN  1913 


Rate  of  planting 
(bushels  per  acre) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 

fertilizer 

Less  than  10 

38 

108  2 

8  2 

$  9  09 

10-12 

62 

119  6 

10  3 

10  54 

12-14 

111 

120  1 

12  4 

11  29 

14-16      . 

69 

137  5 

14  5 

12  73 

16  and  more   . 

20 

163  2 

18  3 

12  14 

Total    .  .    . 

300 

Average   . 

126  2 

12  5 

$11  28 

even  the  growers  who  planted  the  most  seed  did  not  exceed  the  optimum 
rate.  A  coefficient  of  correlation  of  0.247  ±  0.037  between  rate  of  plant- 
ing and  yield  for  this  region  in  1913  is  shown  in  figure  142. 


FIG.  142. 


8 


8 


Yield  per  acre,  in  bushels 
c\i        LQ        i^*        ^5        c^j 


iO 

<M 


O 

CO 


6 

1 

7 

1 

1 

1 

2 

1 

8 

1    4 

7 

2 

5 

1 

9 

1    1 

6 

1 

1 

1 

10 

1    1   8 

8 

9 

11 

2 

6    1 

11 

4 

5 

3 

2 

2 

1 

12 

2   10 

22 

15 

9 

9 

53           11 

13 

1    2 

4 

8 

12 

3 

1    1    1 

14 

4 

7 

6 

5 

4 

3    L   1 

15 

1    3 

6 

4 

"9 

8 

4    1    1 

16 

3 

1 

3 

111 

17 

1 

1 

18 

1 

2 

1 

19 

1 

20 

1 

21 

22 

1 

23 

1 

1 
6 
20 
11 
47 
17 
77 
33 
31 
37 
10 
2 
4 
1 
1 
0 
1 
1 

1    7   38   70   50   61   34   24   8   4   0    1    1    1   300 
r  =  0.247  ±  0.037 

CORRELATION    OF   RATE    OF    PLANTING   AND    YIELD    ON   300  MONROE  COUNTY   FARMS 

IN  1913 


1230 


EARLE  V.  HARDENBURG 


Rate  of  planting  in  Franklin  and  Clinton  Counties 

The  growers  in  Franklin  and  Clinton  counties  who  were  interviewed 
concerning  their  1913  crop  planted  an  average  of  12  bushels  of  seed  per 
acre,  the  rate  varying  from  less  than  10  to  more  than  18  bushels.  The 
relation  of  this  factor  to  yield  in  1913. is  shown  in  table  62.  A  study  of 


TABLE  62. 


RELATION  OF  RATE  OF  PLANTING  TO  YIELD  ON  300  FRANKLIN  AND  CLINTON 
COUNTY  FARMS  IN  1913 


Rate  of  planting 
(bushels  per  acre) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount 
of  seed 
used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

Less  than  10  

38 

151  7 

8  5 

$12  72 

10-12     

88 

167  0 

10  4 

13  20 

12-14  

105 

188.1 

12.3 

12  48 

14r-16  

52 

185.6 

14.6 

14.06 

16  and  more  

17 

226.1 

17.9 

12.45 

Total  

300 

Average  

179.3 

12.0 

$13.01 

S 
S, 


6 

7 
8 
9 

10 
11 
12 
13 
14 
15 
]6 
17 
18 
19 
20 


Yield  per  acre,  in  bushels 


£ 

i 
o 

£ 

i—  i 

10 

rH 

r\ 

£'- 

£ 

i 
1—  i 

g 

<N 

1 

2 

1 

1 

2 

2 

3 

1 

3 

1 

2 

3 

7 

1 

7 

1 

5 

8 

13 

14 

9 

11 

2 

1 

2 

3 

4 

1 

9 

2 

2 

1 

6 

8 

18 

22 

11 

6 

5 

1 

1 

6 

2 

7 

4 

6 

1 

2 

4 

6 

6 

1 

3 

1 

1 

3 

6 

8 

6 

4 

2 

1 

1 

1 

3 

1 

2 

1 

1 

3 

1 

1 

2 

12        27 


26 


14 


1 

4 

12 

21 

63 

24 

77 

27 

23 

31 

6 

2 

5 

0 

4 


300 


50        52        76        38 
r  =  0.367  ±  0.034 

FlG.   143.       CORRELATION   OF   RATE   OF' PLANTING   AND   YIELD   ON   300   FRANKLIN  AND    CLINTON 

COUNTY   FARMS   IN    1913 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1231 

this  table  shows  that  there  was  less  tendency  in  this  region  than  in  the 
others  for  growers  using  the  most  seed  to  use  also  the  most  manure  and 
fertilizer.  The  figures  are  therefore  all  the  more  conclusive  in  showing 
the  marked  influence  of  rate  of  planting  on  yield.  More  seed  than  the 
amount  indicated  by  the  highest  rate  of  planting  here  reported  might 
have  been  used  with  profit  in  raising  the  1913  crop.  The  coefficient  of 
correlation,  0.367  =b  0.034  (fig.  143),  is  altogether  significant  and  is  the 
second  largest  value  found  for  any  of  the  four  regions  *  surveyed. 

DATE    OF  PLANTING 

The  average  date  of  planting  potatoes  in  any  region  is  determined  pri- 
marily by  the  average  date  of  the  last  killing  frost  in  the  spring,  altho 
elevation,  soil  type,  and  the  type  of  potato  grown,  are  also  important 
questions  varying  with  different  localities.  Thus  it  is  possible  to  plant 
earlier  on  light  soils  and  at  lower  elevations,  than  on  heavy  soils  and  at 
higher  elevations.  However,  because  of  the  higher  prices  which  usually 
obtain  early  in  the  harvest  season,  the  earliest  possible  planting  and 
harvest  of  early  varieties  is  desirable. 

Zavitz  (1916)  reported  results  from  thirty-six  tests  which  consisted  of 
planting  two  early,  two  medium,  and  two  late  varieties  on  four  dates, 
two  weeks  apart,  extending  from  May  31  to  July  12.  He  carried  this 
experiment  thru  a  period  of  six  years.  Without  exception,  in  all  six 
varieties,  both  marketable  and  total  yield  increased  directly  with  the 
earliness  of  planting.  A  continuation  of  this  test  the  following  year, 
with  the  plantings  made  on  six  dates  instead  of  on  four,  gave  the  same 
general  results.  These  tests  were  conducted  on  ordinary  clay  loam  soil 
at  the  Guelph  station.  Champlin  and  Winright  (1917)  compared  for  two 
years  the  yields  from  planting  at  intervals  of  fifteen  days  from  April  1 
to  July  1.  For  early  digging  the  April  1  planting,  and  for  late  digging 
the  May  15  planting,  gave  the  best  average  yield  for  the  two  years.  Such 
results  as  these  are  of  value,  even  locally,  only  when  the  tests  cover  a 
period  of  several  years. 

Because  of  the  small  variation  in  date  of  planting  within  each  region 
surveyed  for  the  one  year,  and  because  of  the  fact  that  conclusions  on  the 
best  time  to  plant  cannot  be  drawn  from  the  yield  of  only  one  season,  no 
attempt  has  been  made  to  correlate  the  date  of  planting  and  the  yield. 
The  average  date  of  planting  in  1912  and  in  1913,  and  the  average  date  of 
the  last  killing  frost  in  the  spring,  for  the  four  regions,  are  shown  in  table 
63.  The  dates  shown  in  this  table  indicate  that  Long  Island  is  the  only 
region  in  which  the  crop  is  planted  before  the  average  date  of  the  last 
killing  spring  frost.  It  is  evident  that  the  Long  Island  growers  are  willing 
to  risk  possible  damage  to  the  crop  from  frost  in  order  to  enhance  the 
earliness  of  harvest.  The  planting  season  of  this  region  is  shown  to  be 
at  least  six  weeks  earlier  than  that  of  the  others. 


1232 


EARLE  V.  HARDENBURG 


TABLE  63. 


AVERAGE  DATE  OF  PLANTING,  AND  AVERAGE  DATE  OF  LAST  KILLING  FROST 
IN  SPRING,  FOR  THE  FOUR  REGIONS  SURVEYED 


Region 

Average  date 
of  planting 

Average  date  of 
last  killing  frost 
in  spring 

Long  Island,  1912  

April    9 

April  25 

Steuben  County,  191$ 

h     :.  , 

May  20 

May  10 

Monroe  County,  1913 

May  24 

May    1 

Franklin  and  Clinton 

Counties,  1913  

May  30 

May  10 

HAND  AS    COMPARED  WITH  MACHINE  PLANTING 

The  extent  to  which  the  potato  crop  of  any  region  is  planted  by  machine 
planters  is  determined  principally  by  the  average  acreage,  the  system  of 
spacing  hills  in  the  row,  and  the  amount  of  large  stones  present  in  the 
fields.  The  writer  (Hardenburg,  1915  a)  found  that  in  Steuben  County, 
in  1912,  when  the  average  acreage  of  potatoes  per  farm  was  at  least  5, 
the  saving  in  labor  cost  by  machine  planting  more  than  overbalanced  the 
interest,  depreciation,  and  repair  costs  of  planting  by  this  method.  In 
regions  where  checkrowing  is  practiced,  machine  planting  is  impossible 
because  potato  planters  cannot  be  used  to  plant  in  checkrows.  As  is 
shown  later,  much  of  the  acreage  in  Steuben  County  was  planted  in  this 
way  in  1912.  Some  growers  in  Franklin  and  Clinton  Counties  find  it 
impracticable  to  use  planters  because  there  are  so  many  large  stones  in 
their  fields.  Conditions  on  Long  Island,  however,  are  almost  ideal  for 
machine  planting,  and  it  is  done  there  almost  entirely.  The  extent  to 
which  the  acreage  in  each  region  was  planted  by  hand  and  by  machine, 
in  the  two  years  concerned,  is  shown  in  table  64: 


TABLE  64. 


METHOD  OF  PLANTING  AND  TYPE  OF  MACHINE  USED  IN  THE  FOUR  REGIONS 
SURVEYED 


Region 

Per  cent  of  total  acreage 
planted  by 

Per  cent  of  total  machine- 
planted  acreage  planted 
by 

Machine 

Hand 

2-man 
planter 

1-man 
planter 

Long  Island,  1912  

98 
25 

74 
82 

2 
75 
26 

18 

23 
60 
87 
56 

77 
40 
13 
44 

Steuben  County,  1912  

Monroe  County,  1913  

Franklin  and  Clinton  Counties,  1913 

Average  

70 

30 

56 

44 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1233 

It  might  be  presumed  that  growers  of  the  larger  acreages  in  each  region 
would  be  more  inclined  to  use  planters  than  those  having  a  smaller  acreage. 
Whether  this  was  true  in  these  four  regions  is  shown  in  table  65 : 

TABLE  65.      RELATION  OF  SIZE  OF  POTATO  ACREAGE  TO  METHOD  OF  PLANTING 


Region 

Average  potato 
acreage  per 
farm 

Average  potato 
acreage  planted 
by  machine 

Average  potato 
acreage  planted 
by  hand 

Long  Island,  1912  

24  8 

24.6 

33.5 

Steuben  County,  1912  

14  6 

17.9 

13.7 

Monroe  County,  1913  
Franklin  and  Clinton  Counties,  1913 

12.4 

7.2 

13.1 
6.5 

10.6 
8.6 

It  is  evident  that  growers  in  none  of  these  regions  find  it  unprofitable  to 
plant  by  machine  so  far  as  average  acreage  of  the  crop  is  concerned.  In 
Steuben  and  Monroe  Counties  there  was  a  tendency  to  use  more  planters 
on  the  larger  acreages.  The  2  per  cent  of  acreage  on  Long  Island  planted 
by  hand  averaged  higher  per  farm  than  the  balance  which  was  machine- 
planted.  The  same  relation  held  with  the  18  per  cent  of  hand-planted 
acreage  in  Franklin  and  Clinton  Counties.  It  is  clear,  from  tables  64 
and  65,  that  the  average  potato  acreage  per  farm,  considered  in  the  light 
of  percentage  of  total  acreage  planted  by  hand  and  by  machine  in  each 
region,  has  no  bearing  on  the  extent  of  machine  planting  in  these  four 
regions. 

As  indicated  in  table  64,  two  types  of  planters  were  commonly  used. 
One  was  of  the  picker  type,  employing  only  one  man,  while  the  other 
was  usually  of  the  platform  type  and  required  two  men  for  its  opera- 
tion. As  the  second  man  on  a  two-man  planter  is  charged  with  the  duty  of 
seeing  that  there  are  no  skips,  better  stands  of  potatoes  are  expected  from 
this  type  of  planter.  It  is  shown  in  table  64  that,  whereas  about  three- 
fourths  of  the  Long  Island  acreage  was  planted  with  one-man  planters, 
the  two-man  type  predominated  in  the  other  three  regions. 

A  study  of  the  relative  yields  obtained  from  the  acreage  planted  with  each 
type  in  the  four  regions  is  shown  in  table  66.  Of  the  total  of  635  growers 
using  machine  planters  —  about  one-half  of  all  the  farmers  visited  —  the 
numbers  using  each  type  of  planter  were  approximately  equal.  The 
weighted  averages  in  table  66  show  that  with  about  the  same  amount  of 
seed  per  acre  used  in  each  planter,  the  yield  was  19.3  bushels  per  acre 
higher  from  the  acreage  planted  with  the  one-man  planter.  This  average 
is  not  a  true  criterion  of  the  two  types  of  planters,  however,  because  a 
large  proportion  of  the  total  machine-planted  acreage  was  on  Long  Island, 


1234  EARLE  V.  HARDENBURG 

TABLE  66.     RELATION  OF  TYPE  OF  PLANTER  TO  YIELD  IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Two-man  planter 

One-man  planter 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Long  Island,  1912  
Steuben  County,  1912  .  .  . 
Monroe  County,  1913.  .  . 
Franklin      and      Clinton 
Counties,  1913  

74 
43 
175 

22 

171.6 
158.1 
132.1 

196.4 

12.5 
11.8 
13.2 

14.7 

249 

28 
28 

16 

175.6 
148.8 
116.3 

181.8 

12.5 
12.9 
13.2 

14.4 

Total 

314 

321 

Weighted  average 

151.4 
164.6 

12.8 
13.1 

170.7 
155.6 

12.6 
13.2 

Unweighted  average  

where  77  per  cent  of  the  machine-planted  area  was  planted  with  the  one- 
man  type  of  planter.  On  the  contrary,  the  difference  in  average  yield, 
even  on  Long  Island,  was  only  4  bushels  per  acre  in  favor  of  the  picker 
planter,  a  difference  so  small  as  to  lie  within  expected  probable  error.  In 
the  other  three  regions,  where  approximately  equal  rates  of  planting 
were  used,  the  average  yields  favored  the  two-man  planter  by  differences 
ranging  from  9.3  to  15.8  bushels  per  acre.  The  unweighted  averages  in 
the  table  furnish  a  true  comparison  of  the  efficiency  of  the  two  types  of 
planters,  and  may  be  accepted  as  an  indication  of  the  increased  yield  from 
a  more  perfect  stand  resulting  from  the  use  of  the  extra  man  on  the  plat- 
form planter. 

CHECKROW    AS    COMPARED   WITH  DRILL  PLANTING 

A  decision  as  to  whether  to  plant  potatoes  in  checkrows  or  in  drills 
involves  such  factors  as  the  cost  of  labor,  available  soil  fertility  and  mois- 
ture, land  value,  weed  control,  and  the  use  of  machine  planters.  Of  these 
factors,  weed  control  is  probably  the  most  influential.  The  statements  of 
many  growers  in  Steuben  County  concerning  their  reason  for  checkrow 
planting  emphasized  the  facility  of  weed  control  by  cross  cultivation  in 
times  when  hand  labor  is  scarce  or  when  the  pressure  of  other  farm  work  or 
a  wet  season  might  make  weed  control  otherwise  difficult.  The  cost  of 
labor  as  a  determining  factor  is  debatable,  for,  while  checkrowing  may 
reduce  to  a  minimum  the  cost  of  taking  care  of  the  crop,  the  seed  may  be 
planted  at  less  cost  when  planters  are  used,  and  planters  cannot  be  used 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1235 

to  plant  the  hills  in  checkrows.  Moreover,  while  a  marker  is  carried  by 
the  machine  planter,  extra  labor  is  necessary  to  mark  the  field  in  checks 
for  checkrow  planting.  As  is  shown  in  later  tables,  less  seed  per  acre  is 
usually  planted  by  the  checkrow  system  than  by  the  drill  method,  since 
the  seed  pieces  are  spaced  farther  apart.  Therefore,  from  the  standpoint 
of  land  economy,  checkrowing  is  the  less  desirable  method  where  land  is 
high  in  value,  as  on  Long  Island.  An  ample  spacing  between  hills  is  shown 
by  the  typical  checkrowed  field  in  Steuben  County  illustrated  in  figure  144. 


FlG.  144.      A    CHECKROWED    POTATO    FIELD,    COMMON   IN   STEUBEN    COUNTY 

The  smaller  amount  of  seed  planted  per  unit  of  space  in  the  checkrow 
system  may  be  desirable  wherever  soil  moisture  and  fertility  are  likely  to 
be  taxed  to  their  limit.  However,-  the  foregoing  studies  on  the  relation 
between  rate  of  planting  and  yield  do  not  indicate  that  this  point  was 
reached  in  Steuben  County  in  1912. 

Harwood  (1893)  reported  comparative  yields  from  twenty-four  experi- 
ments conducted  at  the  Michigan  station,  in  which  the  varieties  Early 
Ohio  and  Rural  New  Yorker  No.  2  were  planted  in  hills  and  in  drills. 
These  tests  are  especially  valuable  because  equal  amounts  of  seed  per  acre 
were  used  in  both  systems  of  planting.  Altho  drill  planting  did  not 
always  give  the  higher  yield,  the  general  average  showed  a  difference  of 
12  bushels  per  acre  for  the  Early  Ohio  and  29  bushels  for  Rural  New 


1236 


EABLE  V.  HARDENBURG 


Yorker  No.  2  in  favor  of  this  method.  These  differences  were  due, 
not  to  a  difference  in  rate  of  planting,  but  to  the  system  of  spacing 
the  seed  pieces.  Shepperd  and  Churchill  (1911),  using  the  variety  Early 
Ohio  and  varying  the  rate  of  planting  according  to  the  space  between 
seed  pieces,  compared  the  yields  from  planting  at  distances  of  from  10  to 
36  inches  in  the  row.  Here  the  yield  decreased  directly  as  the  interspace 
increased,  the  10-inch  spacing  giving  the  best  yield.  Zavitz  (1916),  in  a 
six-years  test,  using  equal-sized  large  whole  seed  and  equal-sized  medium 
whole  seed,  compared  the  results  of  spacing  the  seed  1,  2,  and  3  feet. 
While  his  total  yields  increased  directly  as  the  spacing  decreased,  he 
obtained  the  largest  net  yield  from  the  2-foot  spacing  of  large  whole  seed 
and  from  the  1-foot  spacing  of  medium  whole  seed.  In  another  test, 
running  for  nine  years  and  with  the  same  rate  of  planting  in  both  systems 
of  spacing,  he  compared  the  yields  from  planting  in  checks  33  inches 
apart  and  from  planting  in  the  drill  row  with  the  seed  pieces  1  foot  apart. 
The  results  showed  a  nine-years  average  difference  of  39.8  bushels  per 
acre  in  favor  of  the  drill-planted  seed.  From  a  review  of  the  tests  here 
reported,  it  appears  that,  irrespective  of  ral^e  of  planting,  the  yield  from 
planting  in  drills  is  generally  better  than  that  from  planting  in  checkrows. 
None  of  the  330  Long  Island  growers  who  were  questioned  regarding 
their  1912  crop  had  planted  in  checkrows.  The  almost  universal  use  *of 
planters  in  this  region  precludes  the  possibility  of  planting  by  the  check- 
row method.  Furthermore,  the  greater  land  values  encourage  economy 
of  space,  and  the  better  yields  from  closer  planting  have  convinced  the 
growers  of  this  region  that  drill  planting  is  the  better  method.  The  method 
of  planting  most  common  in  each  of  the  four  surveyed  regions  is  indicated 
in  table  67 : 

TABLE  67.    SYSTEM  OF  PLANTING  IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Per  cent  of 
growers  planting 
in  drills 

Per  cent  of 
growers  planting 
by  checkrow 

Long  Island   1912 

100 

0 

Steuben  County,  1912  

29 

71 

Monroe  County   1913 

74 

26 

Franklin  and  Clinton  Counties,  1913                   .    . 

18 

82 

In  contrast  to  the  conditions  on  Long  Island,  approximately  three-fourths 
of  the  crop  in  Steuben  and  in  Franklin  and  Clinton  Counties  was  planted  in 
checkrows.  This  may  be  accepted  as  evidence  that  relatively  cheap  land 
and  scarcity  of  labor  make  this  the  better  method  for  these  regions.  About 
three-fourths  of  the  Monroe  County  crop  was  planted  in  drills  in  1913. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1237 


The  influence  of  the  planting  system  on  yield  and  on  the  amount  of  seed 
used  is  strikingly  shown,  for  these  three  regions,  in  table  68.  As  is  indicated 
in  this  table,  in  all  three  regions  the  drill  system  of  planting  gave  an  average 

TABLE  68.    RELATION  OF  PLANTING  SYSTEM  TO  YIELD  IN  THREE  OF  THE  REGIONS  SURVEYED 


Region 

Planted  in  drills 

Planted  by  checkrow 

Num- 
ber 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount 
of  seed 
used 
per 
acre 
(bushels) 

Average 
value 
of 
manure 
and 
fertilizer 

Num- 
ber 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount 
of  seed 
used 
per 
acre 
(bushels) 

Average 
value 
of 
manure 
and 
fertilizer 

Steuben  County,  1912.  .  . 
Monroe  County,  1913  .  .  . 
Franklin      and      Clinton 
Counties,  1913  

101 
221 

54 

153.0 

128.5 

188.4 

12.2 
13.2 

14.5 

$12.09 
11.91 

12.94 

251 

77 

243 

129.2 
120.6 

177.2. 

9.2 
10.2 

11.4 

$  9.35 
9.68 

13.20 

Total 

376 

571 

Average  

156.6 

13.3 

$12.31 

.... 

142.3 

10.3 

$10.74 

yield  varying  from  7.9  to  23.8  bushels  per  acre  higher  than  that  from  plant- 
ing in  checkrows.  It  is  shown  further  triat  invariably  about  3  bushels 
more  of  seed  per  acre  was  required  to  plant  by  the  drill  system.  The 
yield  was  sufficiently  higher  from  this  method,  however,  to  more  than 
pay  for  the  extra  seed  necessary. 

On  the  basis  of  yield  alone,  these  results  favor  the  drill  system  of  planting 
for  all  the  regions  surveyed.  However,  it  is  possible  that  there  are  seasons 
in  which  weed  control  is  largely  dependent  on  the  possibility  of  cross 
cultivation.  The  choice  at  such  times  becomes  one  of  producing  a  medium 
yield  by  checkrow  planting  with  a  minimum  of  labor,  or  a  much  smaller 
yield  by  drill  planting. 

DEPTH    OF   PLANTING 

Depth  of  planting  is  a  factor  which,  tho  given  some  experimental  atten- 
tion by  various  stations  for  many  years,  has  received  little  consideration 
from  the  potato  grower.  The  depth  at  which  the  seed  piece  is  usually 
placed  depends  principally  on  the  soil  type  and  the  method  of  planting. 
Just  as  plowing  and  tillage  are  normally  more  shallow  in  heavy  than  in 
light  soil,  so  potatoes  are  normally  planted  less  deeply  in  heavy  than  in  light 
soil.  However,  the  depth  at  which  the  potato  root  system  is  allowed  to 
develop  depends  not  alone  on  the  depth  of  planting,  but  also  on  the  system 
of  tillage  employed.  This  is  a  factor  too  often  neglected  in  the  study  of 
the  influence  of  depth  of  planting  on  yield.  For  example,  the  seed  may 
be  planted  shallow  and  the  crop  given  ridge  culture,  or  the  seed  may  be 
planted  deeper  and  the  crop  receive  level  culture.  With  either  method 


1238  EARLE  V.  HARDENBURG 

the  root  system  might  develop  at  exactly  the  same  depth.  Therefore,  in 
studying  this  factor  by  reviewing  experimental  data,  false  conclusions 
may  easily  be  drawn.  In  studying  it  by  survey  methods,  however,  the 
problem  is  not  so  complicated,  because  of  the  fact  that  approximately 
the  same  system  of  culture  is  used  thruout  a  given  locality. 
.  Harwood  (1893)  reported  a  test  of  depth  of  planting  conducted  at  the 
Michigan  station,  using  three  varieties  and  planting  on  sandy  loam  soil. 
The  depth  of  planting  was  varied  from  2  to  6  inches.  The  highest  total 
yield  came  from  the  3-inch  planting,  while  the  4-inch  depth  was  second  best. 
The  highest  marketable  yield  came  from  planting  5  inches  deep,  altho  there 
was  practically  no  difference  between  this  and  the  4-  and  6-inch  depths. 
Emerson  (1907)  compared  the  yields  from  plantings  at  from  1-  to  6-inch 
depths,  and  obtained  a  constant  increase  in  yield  with  each  increase  in 
depth  up  to  and  including  5  inches.  The  6-inch  depth  gave  the  second 
highest  yield.  Emerson  concluded  that  the  better  quality  and  shape  of 
the  tuber  resulting  from  planting  from  4  to  5  inches  deep,  more  than  offset 
the  extra  labor  of  digging  necessary  for  these  depths.  Sandsten  and 
Delwiche  (1909)  harvested  the  highest  total  yield  from  the  4-inch  depth  of 
p  lanting,  the  yield  decreasing  with  the  increase  in  depth  below  that  level. 
Shepperd  and  Churchill  (1911)  compared  the  yields  from  plantings  at 
depths  of  3,  4,  5,  6,  7,  and  8  inches.  The  4-inch  depth  gave  8  per  cent 
higher  yield  than  any  deeper  planting,  and  4.5  per  cent  more  than  the 
3-inch  depth.  These  investigators  did  not  mention  soil  type,  but  reported 
the  greatest  yield  of  marketable  tubers  and  the  highest  quality  from  the 
deeper  plantings. 

Emerson  (1914),  studying  the  influence  of  depth  of  planting  on  the  value 
of  the  harvested  crop  for  seed  purposes,  planted  at  1,  4,  and  7  inches. 
Seed  from  the  7-inch  planting  yielded  the  best,  both  in  total  and  in  market- 
able yield,  in  both  of  the  tests  he  conducted.  Also,  seed  from  the  4-inch 
planting  yielded  much  better  than  did  that  from  the  1-inch  depth.  Accord- 
ing to  Emerson,  the  higher  quality  of  the  seed  from  such  deep  planting  is 
probably  due  to  the  fact  that  it  was  produced  under  soil  conditions  which 
fluctuated  very  little  in  temperature  and  moisture. 

Clement  and  Werner  (1917)  did  not  mention  soil  type  in  reporting  a 
six-years  test  on  planting  at  depths  of  3,  4,  5,  6,  8,  and  10  inches.  They 
obtained  the  highest  marketable  yield  from  the  4-inch  depth,  and  there  was 
a  fairly  consistent  decrease  in  yield  from  plantings  above  and  below  that 
depth.  Macouri  (1905)  made  a  thoro  test  of  the  influence  of  depth  of 
planting,  by  comparing  the  yields  for  six  years,  on  sandy  loam  soil,  from 
planting  at  depths  of  from  1  to  8  inches.  In  every  one  of  the  six  years  he 
obtained  the  best  yield  from  the  1-inch  depth  of  planting.  The  second- 
best  average  yield  came  from  the  3-inch  planting.  Since  Macoun  explained 
that  cultivation  during  each  season  eventually  placed  the  seed  at  a  depth 
of  about  2J  inches,  it  cannot  be  correctly  concluded  that  1  inch  was  a 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1239 


better  depth  to  plant  than  3  inches.  Macoun's  yields  decreased  rapidly 
in  the  plantings  that  were  deeper  than  6  inches.  Zavitz  (1916),  using  the 
clay  loam  soil  at  the  Ontario  station  for  seven  years,  planted  seed  1,  3,  5, 
and  7  inches  deep,  and' practiced  level  cultivation.  He  obtained  the  best, 
and  practically  equivalent,  yields  from  planting  3  and  5  inches  deep.  He 
noted  that  when  his  seed  was  planted  either  shallower  or  deeper  than  4 
inches,  the  new  tubers  showed  a  tendency  to  develop  nearer  the  4-inch 
level  than  at  the  depth  of  planting. 

The  evidence  presented  in  the  foregoing  experiments  indicates  that, 
depending  to  some  extent  on  the  soil  type  and  the  kind  of  tillage,  the  yields 
are  usually  better  when  the  seed  is  planted  about  4  inches  deep  than  when 
it  is  planted  either  shallower  or  deeper.  The  fact  that  tubers  tend  to 
form  near  the  4-inch  level,  irrespective  of  depth  of  planting,  is  in  itself  an 
indication  that  soil  moisture  and  temperature  are  the  most  favorable  at 
this  depth.  While  seed  planted  deeper  is  normally  subjected  to  tempera- 
tures too  cool  for  rapid  growth,  and  the  resulting  crop  forms  too  deep  to 
be  dug  easily,  seed  planted  less  deep  is  subjected  to  a  greater  fluctuation 
in  moisture  and  temperature,  resulting  in  ill-shaped  tubers  and  very  often 
in  a  high  proportion  of  sunburned  or  even  blighted  tubers. 

In  this  investigation  an  attempt  was  made  to  determine  whether  soil 
type  and  method  of  planting  have  any  influence  on  depth  of  planting. 
The  average  depth  of  planting  in  each  region,  by  machine,  by  hand,  and 
for  the  region,  is  shown  in  table  69: 

TABLE  69.    DEPTH  OF  PLANTING  IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Average 
depth 
planted 
(inches) 

Average 
depth 
planted 
by  machine 

(inches) 

Average 
depth 
planted 
by  hand 
(inches) 

Long  Island,  1912  
Steuben  County,  1912  

3.3    , 
3  1 

3.3 
3  0 

3.4 
3  1 

Monroe  County,  1913  

3  2 

3  1 

3  0 

Franklin  and  Clinton  Counties,  1913     .  . 

2  6 

3  2 

2  5 

Of  the  four  regions,  the  deepest  planting  is  found  on  Long  Island  and 
the  shallowest  in  Franklin  and  Clinton  Counties.  Inasmuch  as  the 
potato  soils  of  these  two  regions  are  lighter  than  those  of  either  Steuben  or 
Monroe  County,  no  influence  of  soil  type  on  depth  of  planting  is  evident 
in  this  study.  The  only  significant  influence  of  method  of  planting  on 
depth  is  in  Franklin  and  Clinton  Counties,  where  machine-planted  potatoes 
were  placed,  on  the  average,  0.7  inch  deeper  than  those  planted  by  hand. 
Whether  or  not  the  average  depth  of  planting  shown  for  each  region 


1240 


EARLE  V.  HARDENBURG 


approximates  the  optimum  depth  is  considered  in  the  following  paragraphs 
and  tables. 

The  relation  of  this  factor  to  yield  on  Long  Island  in  1912  is  shown  in 
table  70.     The  depth  of  planting  appears  to  have  influenced  the  yield  in 

TABLE  70.  RELATION  OF  DEPTH  OF  PLANTING  TO  YIELD  ON  329  LONG  ISLAND  FARMS  IN  1912 


Depth  planted 
(inches) 

Number 
of  farms 

Average 
yield 
per  acre 

(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

Less  than  3 

68 

166  7 

12  1 

$30  25 

3-4.  . 

144 

178  0 

12  5 

32  60 

4-5     . 

99 

176  7 

12  9 

33  41 

5  and  more 

18 

182  2 

12  8 

33  65 

Total     . 

329 

Average,  3.3  inches 

175  6 

12  5 

$32  42 

this  region  very  little.  Altho  the  average  yield  increased  slightly  as  the 
depth  increased,  the  increase  in  yield  beyond  the  3-inch  depth  was  no 
greater  than  would  probably  be  due  to  the  slight  increase  in  seed  and  in 
the  value  of  manure  and  fertilizer  used.  Apparently,  the  average  depth  of 
3.3  inches  for  1912  was  approximately  the  best. 

The  results  of  a  similar  study  in  Steuben  County  are  shown  in  table  71 : 


TABLE  71. 


RELATION  OF  DEPTH  OF  PLANTING  TO  YIELD  ON  360  STEUBEN  COUNTY  FARMS 
IN  1912 


Depth  planted 
(inches) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 

(bushels) 

A  erage 
value  of 
manure  and 
fertilizer 

Per  cent 
of  total 
yield 
rotted  in 
field 

1-2. 

6 

148  1 

10.1 

$  9.39 

1   .0 

2-3  . 

83 

139  6 

10.2 

11.09 

14.5 

3-4.. 

179 

134  4 

10.1 

9.79 

14.7 

4  and  more 

92 

136  0 

10  1 

9.97 

17.4 

Total 

360 

Average,  3.1  inches. 

136.4 

10.1 

$10.06 

15.2 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1241 


Altho  six  growers  are  too  few  to  permit  of  the  drawing  of  definite  conclusions 
as  to  the  shallowest  planting  found,  there  is  considerable  evidence  that 
planting  not  more  than  2  inches  deep  in  the  heavy  soils  of  Steuben  County 
is  desirable,  at  least  in  a  year  as  wet  as  was  1912.  Under  a  constant  rate 
of  planting  at  all  depths,  and  with  the  least  manure  and  fertilizer  used  at 
the  shallowest  depth  of  planting,  this  depth  gave  the  highest  average 
yield  and  the  smallest  percentage  of  field-rotted  tubers  in  1912.  In  fact, 
the  percentage  of  field  rot  increased  with  the  depth  of  planting.  Assuming 
that  there  had  been  no  rot  from  blight  and  wet  weather  that  year,  the 
average  yield  of  the  fields  planted  at  the  shallowest  depth  would  still  have 
been  the  highest. 

The  relation  of  depth  of  planting  to  yield  in  Monroe  County  in  1913  is 
shown  in  table  72.     It  is  clear  from  this  table  that 'in  1913,  planting  shal- 

TABLE  72.     RELATION  OF  DEPTH  OF  PLANTING  TO  YIELD  ON  263  MONROE  COUNTY  FARMS 

IN  1913 


Depth  planted 
(inches) 

Number 
of  farms 

Average 
yield 
per  acre 

(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

1-2.  . 

11 

151  5 

11.5 

$10.43 

:-3  

67 

143  1 

12.8 

11.11 

3-4  

110 

131    * 

12.6 

11.83 

4  and  more    ... 

72 

132  6 

12  5 

11.91 

Total  

260 

Average,  3.2  inches  

135.6 

12.6 

$11.61 

lower  than  the  average  of  this  region  would  have  given  more  than  average 
yields.  With  the  least  seed  and  fertilizer,  the  shallowest-planted  fields 
gave  the  highest  yields.  Since  the  potato  soils  of  this  region  are  heavier 
than  those  of  either  Long  Island  or  Franklin  and  Clinton  Counties,  and, 
in  fact,  are  rather  heavier  than  ideal  potato  soil  should  be,  this  gives  further 
evidence  that  potatoes  should  be  planted  shallower  on  heavy  than  on  light 
soils.  With  an  increase  in  the  value  of  manure  and  fertilizer,  and  an 
approximately  constant  amount  of  seed  used  per  acre,  an  increase  in  depth 
of  planting  was  accompanied  by  decreased  yield  on  fields  planted  deeper 
than  2  inches. 

The  importance  of  depth  of  planting  as  influencing  yield  in  Franklin  and 
Clinton  Counties  is  shown  in  table  73.  The  average  yields  in  this  region 
increased  with  the  depth  of  planting,  down  to  a  depth  of  4  inches.  A  part 
of  this  increase  must  be  attributed  to  an  increased  use  of  seed  and  fertilizer. 


1242 


EARLE  V.  HARDENBURG 


TABLE  73.     RELATION  OP  DEPTH  OF  PLANTING  TO  YIELD  ON  300  FRANKLIN  AND  CLINTON 

COUNTY  FARMS  IN  1913 


Depth  planted 

(inches) 

Number 
of  farms 

Average 
yield 
per  acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

Less  than  2    . 

44 

172  3 

11  2 

$12  27 

2-3.  .  . 

111 

175  4 

11  9 

12  95 

3-4.    ...       

91 

184  9 

12  3 

13  25 

4  and  more  

54 

182.6 

12  4 

13  25 

Total  

300 

Average,  2.6  inches  

179.3 

12  0 

$13  01 

The  evidence  in  table  73  indicates  that  the  yields  began  to  decrease  from 
planting  at  depths  greater  than  4  inches.  Evidently,  in  soils  as  light  as 
those  of  this  locality,  planting  at  greater  depths  than  the  average  of  2.6 
inches  for  1913  may  be  recommended. 

Depth  of  planting  is  a  factor  which  would  require  controlled  experi- 
ments covering  several  years  in  order  to  determine  the  most  effective 
depth  for  any  given  region.  The  evidence  of  a  single  year  from  the  sur- 
veyed regions  indicates  that  in  the  heavier  soils  it  is  safe  to  plant  shallower, 
and  in  the  lighter  soils  deeper,  than  the  average  depth  for  1912  and  1913. 

DEPTH    OF    CULTIVATION 

The  term  cultivation  has  been  used  so  promiscuously  in  agricultural 
literature  that  it  seems  well  to  define  its  limitations  as  used  in  this  study 
before  entering  on  any  discussion  of  its  influence  on  the  yield  of  potatoes. 
Cultivation  has  for  its  primary  objects,  weed  control  and  moisture  con- 
servation. Any  operation  on  the  crop  after  it  is  up,  which  stirs  the  soil 
for  either  or  both  of  these  purposes,  is  therefore  included  within  the  meaning 
of  the  term  as  here  used.  Such  operations  as  using  the  weeder,  pulling 
weeds,  hoeing,  and  hilling  or  ridging  the  crop,  are  comprehended  by  the 
term.  This  will  account  for  the  great  frequency  of  cultivation  noted 
in  the  studies  of  the  influence  of  this  factor  on  yield. 

Harwood  (1893)  reported  the  results  of  forty-four  tests  on  the  influence 
of  depth,  of  cultivation  on  yield.  Considering  1.5  inches  as  shallow  and 
5  inches  as  deep  culture,  forty  of  the  forty-four  tests  gave  total  and 
marketable  yields  favoring  deep  culture.  As  a  rule,  the  greatest  yield  of 
small  and  sunburned  tubers  was  obtained  from  shallow  culture.  Schweit- 
zer (1896),  in  a  one-year  test  on  potatoes  planted  4  inches  deep,  compared 
deep  and  shallow  tillage.  Altho  his  yields  were  almost  equal,  he  obtained 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1243 


a  slightly  higher  marketable  yield  from  deep  cultivation  and  a  slightly 
higher  total  yield  from  shallow  cultivation. 

Information  on  depth  of  cultivation  in  the  four  regions  surveyed,  was 
obtained  in  relative  terms,  denoting  general  depth  rather  than  actual 
inches.  The  variation  in  depth  thruout  the  growing  season  was  noted  also. 
It  has  therefore  not  been  possible  to  make  any  definite  correlation  of  this 
factor  with  yield  in  these  studies,  because  of  the  fact  that  much  variation 
in  opinion  may  have  existed  among  growers  as  to  just  what  constituted 
deep,  medium,  or  shallow  culture.  Furthermore,  it  is  a  common  practice 
in  all  four  regions  to  ridge  the  rows  more  or  less  late  in  the  growing  season. 
This  practice  really  amounts  to  a  deep  cultivation  at  the  center  of  the  row 
while  little  or  none  is  given  close  to  the  plants.  Altho  considerable  varia- 
tion in  the  depth  of  cultivation  was  found  at'  different  times  during  the 
growing  season,  a  plurality  of  the  growers  practiced  relatively  deep  early- 
season  cultivation  and  shallow  late-season  cultivation.  This  would  seem 
to  be  good  cultural  practice,  inasmuch  as  deep  tillage  early  would  enlarge 
the  soil  area  suited  to  tuber  and  root  development,  while  shallower  tillage 
later  would  avoid  undue  root  pruning  and  disturbance  after  tuber  forma- 
tion. 

The  practice  with  respect  to  this  factor,  and  its  apparent  influence  on 
yield  in  each  of  the  regions,  is  shown  in  table  74.  Of  the  1290  growers 

TABLE  74.    RELATION  OF  SEASONAL  DEPTH  OF  CULTIVATION  TO  YIELD  IN  THE  FOUR  REGIONS 

SURVEYED 


Type  of 
cultivaticn 

Long  Island, 
1912 

Steuben  County, 
1912 

Monroe  County, 
1913 

Franklin  and 
Clinton  Counties, 
1913 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber 

of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Deep      early      and 
shallow  late  
Medium  early  and 
medium  late  .... 
Deep      early      and 
deep  late  
Deep      early      and 
medium  late  .... 

267 
9 
34 
12 

172.9 
165.1 
195.0 
149.3 

164 
112 
38 
23 

141.5 
123.3 
149.5 
121.6 

106 
21 
67 
29 

146.0 
130.3 
128.5 
122.9 

89 
68 
35 
30 

183.7 
172.1 
175.4 
196.2 

Total  

322 

337 

223 

212 

Average.  . 

175.2 

135.7 

-   136.7 

181.2 

1244  EARLE  V.  HARDENBURG 

concerned  in  the  whole  survey,  approximately  1100  practiced  one  of  the 
four  types  of  cultivation  listed  in  this  table.  Each  of  the  remainder  prac- 
ticed one  of  the  other  possible  five  types  of  deep,  medium,  and  shallow 
early-  and  late-season  cultivation.  Cn  the  basis  of  weighted  averages,  the 
best  average  yields  were  obtained  from  deep  cultivation  early  in  the  season 
and  shallow  cultivation  late. 

RIDGE   AS    COMPARED    WITH   LEVEL    CULTURE 

The  system  of  potato  culture  in  vogue  almost  universally  thruout  the 
New  England  and  Middle  Atlantic  States  has  been  that  of  varying  degrees 
of  ridging  or  hilling.  An  extreme  ridging,  comparable  to  that  followed  in 
Aroostook  County,  Maine,  is  practiced  in  Franklin  and  Clinton  Counties. 
In  only  a  few  limited  areas,  notably  the  Long  Island  potato  areas,  is  any- 
thing approaching  level  cultivation  common  in  these  sections  of  the 
United  States.  Regardless  of  the  fact  that  several  station  experiments 
have  shown  superior  merit  in  point  of  yield  from  level  culture,  ridge  culture 
is  by  far  the  commoner.  The  more  obvious  advantages  of  ridge  culture 
consist  in  (1)  greater  ease  in  digging,  (2)  more  efficient  weed  control  by 
covering  rather  than  by  removing  and  disturbing  the  root  system  close  to 
the  row,  (3)  more  friable  soil  for  tuber  development,  (4)  protection  of  tubers 
from  the  spores  of  the  late-blight  fungus  (Phytophthom  infestans),  and  (5) 
greater  surface  evaporation  of  moisture,  a  factor  of  special  value  on  heavy 
soils  in  regions  of  possible  excess,  or  poorly  distributed,  growing-season 
rainfall. 

Geismar  (1905)  compared  hill  and  level  culture  on  both  fall-  and  spring- 
planted  potatoes.  His  yields  favored  level  culture  for  both  the  fall-  and 
the  spring-planted  crops  by  5  and  7  per  cent  increases,  respectively.  Geis- 
mar very  mistakenly  added  these  increases  and  credited  the  total  to  the 
advantage  of  level  culture.  This  was  a  blight  year  at  the  Michigan 
station,  and,  altho  Geismar  stated  that  the  damage  from  the  disease  was 
confined  to  the  tops,  it  is  possible  that  some  protection  from  ridging  was 
furnished  the  ridged  plots,  and  that  in  a  dry  year  the  advantage  in  level 
culture  would  have  been  even  greater.  Stone  (1905),  at  the  Cornell 
station,  compared  various  frequencies  of  hilled  and  level  culture  for  five 
years  on  medium  light  soil.  In  each  of  these  years,  the  yields  were  best 
under  level  culture,  the  differences  ranging  from  1  to  37  bushels  per  acre, 
the  average  favoring  level  culture  by  14  bushels.  Stone  did  not  explain 
why  the  smallest  differences  in  yield  occurred  in  the  two  driest  years,  when 
the  greatest  advantage  from  level  culture  might  have  been  expected. 
During  three  of  these  five  years,  he  compared  continuous  level  culture  up 
to  nine  cultivations,  with  laying  by  and  ridging  the  crop  after  from  three 
to  five  cultivations.  In  these  tests,  the  continuous  level  culture  gave  an 
average  advantage  of  54  bushels  per  acre.  Shepperd  and  Churchill 
(1911),  altho  reporting  no  data,  stated  that  level  culture  has  given  far  better 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1245 

results  than  ridging  in  North  Dakota,  even  in  sections  having  the  heaviest 
rainfall. 

•  Since  the  system  of  cultivation  as  well  as  the  depth  of  planting  may  have 
a  part  in  determining  the  ultimate  depth  of  the  seed  piece,  this  factor  of 
depth  of  seed  piece  should  be  controlled  in  all  tests  of  the  influence  of  system 
of  cultivation  on  yield.  Woods  and  Bartlett  (1909)  and  Woods  (1911) 
reported  a  comparison  of  the  yields  from  shallow  planting  and  high  ridging 
and  from  medium  planting  and  medium  ridging.  In  these  tests  the  depth 
of  seed  piece  was  constant.  The  medium-ridge  culture  gave  a  three- 
years  average  yield  of  10  bushels  per  acre  more  than  the  high-ridge  culture. 
Woods  (1914),  reporting  a  continuation  of  these  tests  but  including  deep 
planting  and  level  culture,  showed  a  four-years  average  yield  for  the  years 
1910  to  1913,  inclusive,  of  276  bushels  per  acre  from  medium  ridging,  261 
bushels  per  acre  from  level  culture,  and  232  bushels  per  acre  from  high 
ridging.  Thus,  over  a  long  period  of  years,  in  a  region  of  'relatively  high 
rainfall  and  with  the  depth  of  seed  piece  constant,  the  yields  favored  a 
system  ranging  from  medium-ridge  to  leve.l  culture.  Because  of  the 
greater  difficulty  of  harvesting  the  crop  from  level  culture,  however,  Woods 
concluded  that,  for  Maine  conditions  of  soil  and  climate,  there  is  little 
choice  between  these  three  methods. 

Macoun  (1905)  reported  four-years  average  yields,  from  level  and  from 
ridge  culture,  favoring  ridge  culture  by  22  bushels  per  acre.  Level  culture 
proved  the  better  in  one  of  the  four  years,  and,  altho  one  of  the  four  was 
a  drought  year,  this  was  not  the  year  in  which  the  level  culture  yielded 
the  best.  Macoun's  results  were  obtained  at  the  Ottawa  station,  in  a  moist 
sandy  loam  not  subject  to  drying  out.  Zavitz  (1916),  in  a  nine-years 
test,  obtained  an  average  difference  of  7.6  bushels  per  acre  in  favor  of  ridge 
culture.  He  stated  that  three  of  the  nine  years  were  comparatively  dry, 
and  in  these  three  years  level  culture  gave  the  higher  yields.  Clinton 
(1916),  in  a  six-years  comparison  of  ridge  and  level  culture,  obtained  yields 
slightly  favoring  ridge  culture  during  three  years  and  yields  slightly  favor- 
ing level  culture  during  the  remaining  three  years.  He  concluded  that 
the  only  difference  in  the  influence  of  these  two  systems  on  yield  is  in  an 
advantage  from  a  lower  percentage  of  blight  rot  under  the  ridge-culture 
system. 

It  must  be  concluded  from  the  above  review  of  experiments  that,  in 
general,  level  culture  has  given  slightly  better  yields  than  has  ridging. 
The  advantage  has  been  most  marked  in  dry  years  and  in  the  lighter 
soils.  Depending  on  regional  soil  type  and  seasonal  rainfall,  however, 
the  advantages  generally  conceded  to  ridging  should  be  considered  in  choos- 
ing the  best  system  to  fit  a  specific  locality. 

Owing  to  the  lack  of  variation  in  tillage  methods  within  each  of  the 
regions  studied,  it  was  not  possible  to  correlate  this  factor  with  yield'  by 
survey  methods.  Altho  some  variation  in  the  degree  of  ridging  exists 


1246  EARLE  V.  HARDENBURG      , 

within  each  region,  lack  of  information  on  a  definite  measurement  of  this 
degree  makes  its  use  in  these  studies  impossible. 

Level  culture  is  the  system  generally  understood  to  be  practiced  on  Long 
Island.  However,  nearly  all  the  growers  there,  while  maintaining  level 
culture  thruout  most  of  the  season,  cultivate  a  slight  ridge  toward  the  row 
late  in  the  season,  at  either  the  last  or  the  last  two  cultivations.  The 
reasons  given  by  growers  of  the  1912  crop  for  this  practice,  were  (1)  that 
digging  was  made  easier  and  (2)  that  the  tubers  were  protected  from  the 
spores  of  the  late-blight  fungus.  Altho  the  potato  soils  of  Long  Island  are 
relatively  light  in  texture,  the  growing-season  rainfall  of  this  region,  as 
shown  in  figure  127  (page  1149),  is  relatively  high.  All  growers  of  the 
1912  crop  reported  the  practice  of  level  culture. 

In  Steuben  County  a  system  of  relatively  high  ridging  is  practiced.  A 
ridge  is  gradually  worked  toward  the  row  at  each  cultivation  thruout  the 
season,  and  this  is  increased  late  in  the  season  by  a  specialized  implement 
called  a  killer.  Because  of  the  heavy  soil  of  this  region,  ridge  culture  is 
doubtless  of  some  merit  due  to  the  greater  ease  in  harvesting  and  the 
protection  from  blight  rot  which  it  affords.  All  the  growers  whose  1912 
crop  was  studied  practiced  ridge  culture. 

Of  the  300  growers  in  Monroe  County,  272  reported  the  practice  of 
level  culture,  with  a  slight  ridging  toward  the  end  of  the  growing  season. 
The  other  28  growers  in  this  region  practiced  continuous  level  culture  in 
1913. 

Only  1  of  the  300  growers  in  Franklin  and  Clinton  Counties  practiced 
level  culture  in  1913.  Ridging  is  here  begun  as  soon  as  the  crop  is  up, 
the  tops,  and  such  weeds  as  have  grown  since  planting,  being  covered  at 
that  time.  By  the  end  of  the  growing  season  an  extreme  ridge  has  been 
developed,  greater  than  that  used  in  Steuben  County.  Altho  the  grow- 
ing-season rainfall  of  this  region  is  almost  as  high  as  that  of  Long  Island, 
the  light  soils  which  prevail  in  most  of  the  section  do  not  seem  to  warrant 
such  extreme  ridging.  This  is  a  problem  apparently  impossible  of  solution 
by  survey  methods  and  one  requiring  years  of  test. 

FREQUENCY  OF    CULTIVATION 

Cultivation  as  a  prime  requisite  of  good  crop  yields  thru  its  resulting 
in  weed  control,  moisture  conservation,  and  increased  availability  of  plant 
food,  is  one  of  the  oldest  known  practices  of  agriculture.  However 
very  few  experiments  of  value  have  been  conducted  for  the  express  pur- 
pose of  determining  the  optimum  frequency  of  cultivation.  The  value 
of  such  tests  is,  of  course,  dependent  on  such  other  factors  as  duration  of 
the  experiment,  condition  of  the  seed  bed,  replication,  and  time  of  cultiva- 
tion. Conclusions  drawn  must  give  due  consideration  to  the  available 
soil  moisture  and  fertility  and  the  soil  type  under  which  the  test  is 
conducted. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1247 

Stone  (1905),  in  a  carefully  controlled  experiment  covering  six  years 
at  the  Cornell  station,  compared  the  yields  of  potatoes  from  cultivating 
three,  four,  five,  six,  seven,  eight,  nine,  eleven,  and  thirteen  times  during 
the  season.  During  these  years  he  obtained  average  yields  favoring 
seven,  eight,  and  nine  cultivations,  by  from  8  to  100  bushels  per  acre. 
The  plots  were  replicated  from  two  to  four  times.  Stone's  tests  showed 
clearly  that  under  the  conditions  of  his  experiment  it  was  possible  to  culti- 
vate beyond  the  limit  of  maximum  production.  Emerson  (1907)  compared 
yields  from  what  he  called  poor,  medium,  and  thoro  cultivation.  Under 
poor  tillage,  the  land  was  harrowed  three  times  and  cultivated  twice,  the 
land  not  being  kept  free  from  weeds  even  early  in  the  season.  Under 
medium  tillage,  the  land  was  harrowed  three  times  and  cultivated  four 
times,  the  weeds  growing  only  in  the  rows  after  the  crop  was  nearly  ripe. 
Under  thoro  tillage,  four  harro wings  and  six  cultivations  were  given,  no 
weeds  being  allowed  to  grow.  The  yield  of  the  medium-cultivated  crop 
exceeded  that  from  poor  tillage  by  60  per  cent  and  that  from  thoro  tillage 
by  about  9  per  cent.  Emerson  concluded  (1)  that  tillage  can  be  overdone, 
(2)  that  cultivation  to  control  weeds  only  is  sufficient,  and  (3)  that,  in 
eastern  Nebraska,  two  or  three  harrowings  and  five  or  six  cultivations  are 
sufficient  for  potatoes. 

The  high  frequency  of  cultivation  recorded  for  some  of  the  regions 
included  in  this  study  must  not  be  construed  to  mean  that  this  frequency 
applies  only  to  operations  with  a  cultivator.  As  already  explained,  all 
operations  which  stir  the  soil  and  control  weeds  after  planting  are  included. 
Inasmuch  as  the  rate  of  planting  and  the  value  of  manure  and  fertilizer 
have  already  been  shown  to  be  very  influential  on  yield,  frequency  of 
cultivation  is  here  studied  for  each  region  in  connection  with  these  factors. 

Frequency  of  cultivation  on  Long  Island 

Long  Island  is  the  only  region,  of  the  four  surveyed,  in  which  the  Hal- 
lock  weeder  is  used  extensively.  This  implement  is  used  principally  just 
before  or  just  after  the  crop  comes  up.  Having  a  broad  sweep,  it  removes 
very  efficiently  those  small  weed  seedlings  which  develop  between  planting 
time  and  the  time  at  which  the  plants  come  up.  Since  the  entire  crop  in 
this  region  is  planted  in  drills,  cross  cultivation  is  impossible  and  much 
hand  hoeing  is  therefore  done  to  remove  the  weeds  that  develop  during 
the  growing  season.  Many  growers  reported  also  hand  pulling  of  weeds. 
These  operations,  in  addition  to  the  usual  cultivations  between  the  rows, 
resulted  in  the  highest  frequency  of  cultivation  in  this  region,  the  average 
in  1912  being  10.9  times. 

The  relation  of  this  factor  to  yield,  under  constant  rates  of  planting, 
is  shown  in  table  75.  The  averages  for  the  329  farms  listed  in  this  table 
indicate  that  in  1912  it  did  not  pay  to  cultivate  more  than  ten  times. 
In  fact,  these  averages  seem  to  indicate  that  frequency  of  cultivation  above 


1248 


EARLE  V.  HARDENBURG 


TABLE  75.     RELATION  OF  FREQUENCY  OF  CULTIVATION  AND  RATE  OF  PLANTING,  TO  YIELD, 
ON  329  LONG  ISLAND  FARMS  IN  1912 


Amount  of  seed  planted 

Number  of  times 

Less  than  12 
bushels 

From  12  to  14 
bushels 

14  bushels  and 
more 

Average 

cultivated 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

farms 

per  acre 
(bushels) 

farms 

per  acre 
(bushels) 

farms 

per  acre 
(bushels) 

farms 

per  acre 
(bushels) 

Less  than  10  

44 

183.7 

42 

165.5 

28 

190.9 

114 

176.6 

10-13  

59 

158.7 

52 

183.9 

24 

194.1 

135 

177.1 

13  and  more  

35 

155.7 

32 

157.4 

13 

222.8 

80 

168.6 

Total 

138 

126 

65 

329 

Average 

166.2 

170.2 

197.8 

175.7 

ten  was  not  influential  on  yield.  A  further  study  of  the  table,  however, 
shows  that  as  the  rate  of  planting  increased,  the  efficiency  of  the  higher 
frequencies  of  cultivation  increased.  This  phenomenon  may  possibly 
be  explained  by  considering  it  in  connection  with  the  figures  in  table  76, 

TABLE  76.     RELATION  OF  FREQUENCY  OF  CULTIVATION  AND  VALUE  OF  MANURE  AND  FERTI- 
LIZER, TO  YIELD,  ON  330  LONG  ISLAND  FARMS  IN  1912 


Value  of  manure  and  fertilizer 


Number  of  times 
cultivated 

Less  than  $30 

From  $30  to  $40 

$40  and  more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  10.  . 
10-13  

32 

57 
40 

175.3 
155.7 
151.1 

65 
62 

26 

181.2 
191.2 
163.1 

18 
16 
14 

166.5 
191.9 
217.9 

115 
135 

80 

178.4 
177.1 
168.6 

13  and  more  

Total  

129 

153 



48 

330 

Average 

158.7 

182.2 

.... 

194.4 

175.5 

showing  the  relation  of  frequency  of  cultivation  and  value  of  manure 
and  fertilizer  to  yield.     The  variation  in  the  average  yields  in  tables  75 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1249 

and  76  exhibits  a  very  obvious  similarity.  It  is  evident  in  both  tables 
that  more  than  ten  cultivations  were  efficient  only  when  the  greater 
amounts  of  seed  and  of  manure  and  fertilizer  'were  used.  This  may 
indicate  either  that  a  greater  amount  of  tillage  was  necessary  to  control 
the  greater  weed  growth  produced  by  the  increased  fertility,  or  that 
more  tillage  was  necessary  to  make  available  sufficient  plant  food  to 
support  the  increased  stand  of  potatoes.  It  may  be  concluded  that,  on 
the  average,  it  did  not  pay  to  cultivate  potatoes  more  than  ten  times  in 
this  region  in  1912.  The  coefficient  of  correlation  between  this  factor 
and  yield,  as  shown  in  figure  145,  is  -  0.087  ±  0.037.  This  slightly 

Yield  per  acre,  in  bushels 


S      {2 

CM            S3 

3 

2 

I 

0 

126-150 

i 

1 

i 

<N 

CM               CO            CO 

ril                   CO               i-H 

*-O              t^*           C2 

3-  4 

1 

—         1 

1 

5-  6 

•  1 

2 

3 

1 

2 

1 

10 

g 

7-  8 

1 

5 

5 

19 

3 

11 

11 

6 

3 

64 

'75 

9-10 

1        1 

11 

9 

17 

10 

17 

8 

7 

3                   1 

85 

£5 

IP 

11-12 

1 

6 

10 

20 

17 

18 

2 

6 

442 

90 

n 
w 

13-14 

1 

3 

10 

11 

5 

6 

4 

1 

2    •     3 

46 

J 

15-16 

2 

2 

5 

6 

2 

.1 

1 

19 

17-18 

1 

5 

1 

.2 

1 

10 

*c 

19-20 

1 

1 

m 

21-22 

1 

1 

2 

c 

23-24 

1 

1 

£ 

25-26 

0 

27-28 

1 

1 

1        6      27      38      81        43        60        27        23        13          83        330 
r  =  -  0.087  ±0.037 

FlG.    145.       CORRELATION    OF   FREQUENCY    OF    CULTIVATION    AND    YIELD    ON    330    LONG   ISLAND 

FARMS  IN  1912 

negative  value  indicates  that  the  average  frequency  was  a  little  too  high 
for  maximum  production.  However,  the  relatively  high  probable  error 
renders  the  coefficient  insignificant. 

Frequency  of  cultivation  in  Steuben  County 

Cultivation  was  not  so  thoroly  practiced  in  Steuben  County  in  1912,  as 
on  Long  Island,  the  average  frequency  being  7.6  cultivations.  Weed 
control  is  much  more  of  a  problem  here  than  elsewhere  because  of  the 
fact  that  potatoes  are  usually  grown  on  sod  land  of  several  years  standing 
and  on  land  containing  a  considerable  quantity  of  weed  seed  or  stubble. 
Furthermore;  the  seed  bed  is  here  more  poorly  prepared  than  in  most 
other  regions  because  of  the  susceptibility  of  the  soil  to  extreme  puddling. 
Under  these  conditions,  the  factor  of  frequency  of  cultivation  would  be 


1250 


EARLE  V.  HARDENBURG 


expected  to  have  a  direct  positive  influence  on  yield.     The  relationship  of 
this  factor  and  the  rate  of  planting,  to  yield,  is  shown  in  table  77: 

TABLE  77.     RELATION  OF  FREQUENCY  OF  CULTIVATION  AND  RATE  OF  PLANTING,  TO  YIELD, 
ON  349  STEUBEN  COUNTY  FARMS  IN  1912 


Number  of  times 
cultivated 

Amount  of  seed  planted 

From  6  to  10 
bushels 

From  10  to  14 
bushels 

From  14  to  18 
bushels 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

1-4  

78 
67 
2 

122.5 
123.5 
108.3 

70 
97 
15 

135.6 
141.5 
164.2 

4 
10 
6 

168.6 
201.3 
192.1 

152 
174 
23 

130.3 
138.0 
168.4 

4-  7 

7-13 

Total 

147 

182 

20 



349 

Average  

122.8 

141.4 

191.3 

136.4 

Four  of  the  groups  studied  in  table  77  contain  too  few  farms  to  give 
reliable  results,  yet  the  study  shows  clearly  enough  that  the  average  yields 
increased  as  the  frequency  of  cultivation  increased,  irrespective  of  the 


TABLE  78.     RELATION    OF.  FREQUENCY    OF    CULTIVATION    AND    VALUE    OF    MANURE 
AND  FERTILIZER,  TO  YIELD,  ON  147  STEUBEN  COUNTY  FARMS  IN  1912 


Value  of  manure  and  fertilizer 


Number  of  times 

From 

$4  to  $12 

From  i 

U2  to  $20 

From  i 

&20  to  $50 

A\ 

rerage 

cultivated 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

1-  4.. 
4-7  
7-13... 

23 
35 
10 

136.5 
142.4 
166  0 

20 
24 
4 

150.1 

172.5 

169:9 

5 
21 
5 

165.9 
165.7 
173.5 

48 
80 
19 

145.0 
157.0 
168.4 

Total 

68 

48 

31 

147 

Average  .            ... 

145.0 

162.9 

167.1 

155.1 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1251 

rate  of  planting.  To  further  allay  suspicion  that  the  increased  yields, 
apparently  due  to  increased  cultivation,  were  not  in  part  due  to  corre- 
sponding increases  in  the  value  of  manure  and  fertilizer,  a  study  of  this 
factor  in  connection  with  value  of  manure  and  fertilizer  is  presented  in 
table  78.  Altho  comparatively  few  farms  are  involved  in  the  study  in 
this  table,  the  positive  influence  of  frequency  of  cultivation  on  yield 
is  well  shown.  In  contrast  to  Long  Island,  it  is  apparent  that  growers 
in  this  region  did  not  exceed  the  profitable  limit  in  number  of  cultivations 
in  1912.  This  statement  is  further  proved  by  the  coefficient  of  correla- 
tion, 0.231  =t  0.034,  shown  in  figure  146. 

Yield  per  acre,  in  bushels 


o 


1   9 
.  10 

i    H 
I    12 

13 
14 

£    15 
S    16 

18 
19 
20 


1 

1 

2 

1 

2 

3 

1 

2 

4 

5 

10 

10 

10 

1 

1    2   8 

9 

12 

17 

9 

10 

4    1 

2   6 

18 

15 

11 

5 

5 

1      1         1 

1    5 

16 

14 

10 

15 

8 

6 

7 

16 

5 

2 

3 

1 

5 

5 

4 

2 

3 

1    1      1 

2 

6 

4 

2 

4 

1 

1 

1 

1 

1 

1 

2    1 

1 

1 

2 

1 

1 

2 

1 

1 

1 

2 
11 

40 

73 

65 

69 

39 

23 

19 

8 

4 

1 

4 

1 

0 

0 

0 

1 


2   5   26   64   73   78   52   38   9   10   0   2   0   0   1   360 
r  =  0.231  ±0.034 

FlG.   146.       CORRELATION  OF  FREQUENCY  OF  CULTIVATION  AND  YIELD  ON  360  STEUBEN  COUNTY 

FARMS  IN  1912 

Frequency  of  cultivation  in  Monroe  County 

The  common  rotation  of  one  to  two  years  of  cultivated  crops,  followed 
by  two  years  of  grain,  followed  by  only  one  to  two  years  of  hay,  makes 
the  problem  of  weed  control  less  of  a  limiting  factor  to  yield  in  Monroe 
County  than  in  Steuben  County.  The  growing-season  rainfall  for  this 
region,  however,  as  shown  in  figure  127,  is  lower  than  that  for  the  other 
three  areas,  and,  because  of  this,  cultivation  for  moisture  conservation 
might  be  presumed  important.  The  average  frequency  of  cultivation 


1252 


EARLE  V.  HARDENBURG 


in  1913  was  8.1  times.  The  relation  of  this  factor,  in  connection  with 
the  rate  of  planting  and  the  value  of  manure  and  fertilizer,  to  yield,  is 
shown  in  tables  79  and  80,  respectively: 

TABLE  79.     RELATION  OP  FREQUENCY   OF   CULTIVATION   AND   RATE   OP   PLANTING,    TO 
YIELD,  ON  300  MONROE  COUNTY  FARMS  IN  1913 


.  »  .    '. 

Amount  of  seed  planted 

Number  of  times 

Less  than  12 
bushels 

From  12  to  15 
bushels 

15  bushels  and 
more 

Average 

cultivated. 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

Num- 
ber of 

Average 
yield 

farms 

per  acre 

(bushels) 

farms 

per  acre 

(bushels) 

farms 

per  acre 

(bushels) 

farms 

per  acre 
(bushels) 

Less  than  7  

34 

117.1 

29 

117.9 

15 

112.1 

76 

116.6 

7-9.....  

41 

115.3 

50 

114.4 

23 

145.6 

124 

120.8 

9  and  more  

25 

113.2 

54 

133.6 

21 

172.5 

100 

138.8 

Total 

100 

143 

57 

300 

Average  

115.4 

122.7 

150.1 

126.2 

TABLE  80.    RELATION  OP  FREQUENCY  OP  CULTIVATION  AND  VALUE  OF  MANURE  AND 
FERTILIZER,  TO  YIELD,  ON  300  MONROE  COUNTY  FARMS  IN  1913 


Value  of  manure  and  fertilizer 


Number  of  times 
cultivated 

Less  than  $10 

From  $10  to  $20 

$20  and  more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  7  

36 
59 
41 

106.8 
114.2 
120.6 

33 
56 

47 

122.6 
125.9 
150.1 

7 
9 
12 

137.6 
133.9 
159.2 

76 
124 
100 

116.6 
120.8 

138.8 

7-9  

9  and  more  

Total  

136 

136 



28 

300 

Average  

114.4 

134.3 



145.5 

.... 

126.2 

Altho  increased  frequency  of  cultivation  did  not  produce  increased 
yields  for  growers  using  less  than  12  bushels  of  seed  per  acre,  this  does 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1253 


not  apply  to  the  growers  who  used  more  seed.  Furthermore,  since  the 
group  of  growers  using  less  than  12  bushels  of  seed  per  acre  included  those 
who  planted  in  checkrows,  it  was  doubtless  possible  to  control  weeds 
with  fewer  cultivations  than  were  necessary  for  fields  planted  in  drills. 
A  fairly  consistent  positive  influence  of  frequency  of  cultivation  on  yield, 
irrespective  of  the  value  of  manure  and  fertilizer  used,  is  shown  in  table 
80.  It  is  evident  that  the  highest  frequencies  of  cultivation  were  pro- 
ductive of  profitably  increased  yields  except  for  the  few  growers  who, 
because  of  checkrow  planting  which  made  cross  cultivation  possible,  were 
able  to  control  the  weeds  with  fewer  cultivations.  The  coefficient  0.169 
d=  0.038  (fig.  147),  while  small,  is  positive  and  is  significant  in  value. 


s 


Yield  per  acre,  in  bushels 

8      S      K      8      8 


-  & 

^ 

£ 

0    ' 

T—  1 

1 

i—  i 

i—  l           CO           i—  l            CD           i—  i          CO 
O           CM           iO           t—           O         <M 
<N           <M           <N            <M           CO          CO 

4 

1 

1 

1 

5 

1        1 

5 

6 

4 

1 

3 

6 

1 

10 

16 

8 

9 

4 

2 

2 

7 

1 

9 

14 

8 

12 

8 

4 

1        3 

8 

1 

10 

16 

14 

14 

1 

6 

2 

9 

2 

4 

7 

6 

7 

4 

4 

1                                             1 

10 

1 

1 

7 

3 

4 

7 

3 

1 

11 

2 

3 

4 

6 

1 

1        1                  1 

12 

2 

1 

1 

1 

13 

2 

2 

1 

1 

14 

2 

1 

15 

16 

1 

17 

1 

. 

18 

1 

19 

20 

1 

, 

3 

21 

52 

60 

64 

36 

27 

19 

5 

6 

3 

0 

1 

1 

1 

0 

1 


1        7      38      70      50      61      34      24        8        4        0        1        1        1        300 
r  =  0.169  ±0.038 

FlG.    147.       CORRELATION  OF  FREQUENCY  OF  CULTIVATION  AND  YIELD  ON  300  MONROE  COUNTY 

FARMS  IN  1913 

Frequency  of  cultivation  in  Franklin  and  Clinton  Counties 
Cultivation  in  Franklin  and  Clinton  Counties  is  not  generally  continued 
as  late  in  the  growing  season  as  in  most  other  regions  of  the  State.  On 
the  other  hand,  ridging  is  begun  early  in  the  season  and  the  crop  is  given  the 
final  ridging  soon  after  blossoming.  The  average  number  of  cultivations 
in  this  region  in  1913  was  6.3.  As  shown  in  table  15,  this  was  the  only 
region  of  the  four  in  which  a  very  significant  proportion  of  the  total  acreage 


1254 


EARLE  V.  HARDENBURG 


was  plowed  in  the  fall.  This  practice  allows  earlier  and  better  seedbed 
preparation  in  the  spring  than  would  otherwise  be  possible,  and 'makes 
later  cultivations  during  the  growing  season  less  necessary.  The  relation 
of  this  factor  in  connection  with  the  amount  of  seed  and  the  value  of  manure 
and  fertilizer  used,  to  yield,  in  1913,  is  shown  in  tables  81  and  82,  respec- 

-  ABLE  81.     RELATION  OF  FREQUENCY  OF  CULTIVATION  AND  RATE  OF  PLANTING,  TO  YIELD, 
ON  300  FRANKLIN  AND  CLINTON  COUNTY  FARMS  IN  1913 


Number  of  times 
cultivated 

Amount  of  seed  planted 

Less  than  12 
bushels 

From  12  to  14 
bushels 

14  bushels  and 
more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  6  
6-8.  . 

46 
41 
38 

164.1 
162.5 
159.6 

49 
35 
20 

184.0 
192.0 
191.2 

30 
30 
11 

189.0 
204.8 
184.5 

125 
106 
69 

177.2 

187.7 
172.0 

8  and  more    .    . 

Total  

125 

104 

71 

300 

Average             .  . 

162.1 

188.1 

195.0 

179.3 

TABLE  82.     RELATION  OF  FREQUENCY  OF  CULTIVATION  AND  VALUE  OF  MANURE  AND 
FERTILIZER,  TO  YIELD,  ON  297  FRANKLIN  AND  CLINTON  COUNTY  FARMS  IN  1913 


Value  of  manure  and  fertilizer 


Number  of  times 
cultivated 

Less  than  $10 

From  $10  to  $14 

$14  and  more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  6  
6-8  
8  and  more  

44 
31 
19 

173.0 
177.7 
142.5 

41 
38 

27 

177.5 

188.4 
177.0 

38 
37 
22 

189.0 

188.4 
188.9 

123 
106 

68 

179.1 
185.2 
171.5 

Total 

94 

106 

97 

297 

Average  

168.2 

181.3 

188.7 

179.5 

A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1255 


tively.  As  shown  in  these  tables,  there  was  no  apparent  gain  in  yield  in 
1913  from  cultivating  more  than  seven  times.  In  fact,  it  is  question- 
able whether  the  small  gain  shown  in  most  cases  from  cultivating  more 
than  five  times  was  sufficient  to  pay  the  extra  cost  of  the  labor  involved. 
This  means  that  the  average  frequency  for  the  year  concerned  was  not  far 
from  optimum.  The  coefficient  0.055  ±  0.039  (fig.  148),  while  positive,  is 


Yield  per  acre,  in  bushels 


-?  3 

"es  4 

£  5 

3  6 

S  7 

|  8 

I  9 

•s  10 


14 


1 

3 

1 

3 

2 

10 

2    3 

4 

9 

6 

'  5 

3 

32 

3    5 

14 

17 

15 

18 

5 

4    2 

83 

3    4 

12 

•7 

19 

.  5 

9 

2    3 

64 

1    4 

6 

8 

16 

2 

3 

2 

42 

1    5 

6 

3 

8 

3 

2 

1 

29 

5 

2 

3 

1 

1 

3 

15 

1 

2 

3 

2 

1 

1 

10 

1 

1 

1 

3 

1 

1 

1 

3 

1 

1 

6 

' 

2 

2 

1 

5 

12   27 


26 


14 


300 


FIG.  148. 


50   52   76   38 
r  =  0.055  ±  0.039 

CORRELATION  OF  FREQUENCY  OF   CULTIVATION  AND  YIELD   ON   300  FRANKLIN   AND 
CLINTON  COUNTY  FARMS  IN  1913 


too  small  and  insignificant  to  indicate  any  real  correlation  of  frequency  of 
cultivation  with  yield.  It  must  be  concluded,  therefore,  that  in  practically 
all  cases  sufficiently  frequent  cultivation  was  given  so  that  it  was  not  a 
factor  limiting  yield. 

SPRAYING 

Spraying  as  a  factor  in  potato  production  must  have  been  first  practiced 
in  this  country  sometime  after  1859.  This  is  the  date  when  the  Colorado 
potato  beetle  (Leptinotarsa  decemlineatd)  began  its  movement  eastward  from 
the  Rocky  Mountains  (Fraser,  1912).  The  potentiality  of  this  pest  to 
cause  complete  defoliation  has  since  resulted  in  the  extensive  use  of  such 
arsenical  insecticides  as  paris  green,  arsenate  of  lead,  and  arsenite  of 
soda,  for  its  control.  The  extent  to  which  insecticides  have  been  used  in 
a  given  locality  has  depended  on  the  prevalence  of  the  beetles.  The  fact 
that  growers  in  a  certain  locality  did  not  spray  for  insects  during  a  certain 
season,  is  evidence  that  insects  were  scarce  or  almost  absent.  A  study  of 
the  influence  of  spraying  with  insecticides  on  yield  in  a  given  region,  there- 


1256  EARLE  V.  HARDENBURG 

fore,  may  not  be  expected  to  show  positive  results.  On  the  contrary, 
positive  influence  on  the  yield  from  spraying  with  a  fungicide  for  the 
simultaneous  control  of  late  blight  (Phytophthora  infestans) ,  early  blight 
(Alternaria  solani),  and  tipburn,  as  well  as  for  the.  control  of  flea  beetles 
(Epitrix  cucumeris),  may  be  expected  in  most  potato  regions  every  year 
if  the  spraying  is  done  thoroly.  As  a  standard  fungicide,  bordeaux  mix- 
ture has  been  used  for  this  purpose  for  about  thirty-six  years,  the  practice 
having  begun  in  France  in  1885  (Macoun,  1905).  Probably  the  first 
systematic  and  continuous  series  of  spraying  experiments  with  bordeaux 
conducted  in  this  country,  were  begun  by  Jones  at  the  Vermont  station 
in  1891.  Lutman  (1911)  has  reported  a  twenty-years  summary  of  these 
experiments.  During  this  period,  late  blight  occurred  fifteen  years  out  of 
the  twenty,  the  loss  in  yield  from  the  resulting  rot  varying  from  year  to 
year.  These  tests  showed  a  gain  in  yield  every  year  from  spraying,  the 
percentage  of  gain  per  acre  ranging  from  18  in  a  year  of  no  blight,  to  215 
in  a  year  of  much  blight,  and  the  average  gain  per  acre  for  the  twenty 
years  being  64  per  cent.  Altho  the  frequency  of  spraying  in  these  tests 
varied  from  one  to  five  times  a  season,  the  influence  of  spraying  cannot  be 
studied  because  different  frequencies  were  not  used  within  any  one  year. 

Second  in  importance  to  the  Vermont  experiments  are  those  of  ten 
years  duration  conducted  by  the  New  York  station  at  Geneva,  under  the 
direction  of  Stewart,  French,  and  Sirrine  (1912).  These  tests  were  dupli- 
cated, one  series  being  conducted  on  heavy  clay  loam  soil  at  Geneva,  and 
the  other  on  light  sandy  loam  soil  at  Riverhead.  During  the  test,  late 
blight  occurred  six  years  out  of  the  ten  at  Geneva  and  only  three  years  out 
of  the  ten  at  Riverhead.  As  might  be  expected,  therefore,  the  greater 
average  gain  from  spraying  was  obtained  from  the  Geneva  plots.  How- 
ever^ there  was  not  one  year  out  of  the  ten  on  either  series  of  plots  in  which 
a  gain  from  spraying  was  not  obtained.  In  years  of  no  blight  this  gain 
was  attributed  to  the  control  of  such  factors  as  flea  beetles,  early  blight, 
bugs,  and  tipburn.  Spraying  every  two  weeks  during  the  growing  season 
was  each  year  compared  to  spraying  but  three  times.  With  but  one  slight 
exception,  the  more  frequent  spraying  resulted  in  the  higher  yield.  The 
ten-years  average  difference  in  yield  due  to  this  difference  in  frequency  of 
spraying  was  28.5  bushels  per  acre  for  Geneva,  and  20.7  bushels  per  acre 
for  Riverhead.  Spraying  every  two  weeks  gave  a  ten-years  average  gain 
in  yield  of  97.5  bushels  per  acre  at  Geneva  and  45.7  bushels  per  acre  at 
Riverhead. 

Clinton  (1916)  reported  the  results  of  spraying  in  a  thirteen-years 
test  at  the  Connecticut  station.  Altho  no  data  are  presented  on  the 
influence  of  the  various  frequencies  of  spraying,  increased  yields  ranging 
from  10  to  101  bushels  per  acre  (the  average  being  38  bushels  per  acre) 
were  reported.  At  this  station,  also,  increased  yields  due  to  spraying  were 
obtained  every  year,  including  years  of  no  blight,  in  which  the  average 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1257 

increase  was  29  bushels  per  acre.  In  all  but  four  of  twenty-two  tests,  the 
increased  yield  more  than  paid  the  cost  of  spraying,  the  average  net  gain 
per  acre  being  $15. 

Stone  (1905)  varied  the  frequency  of  bordeaux  spraying  from  year  to 
year  in  a  six-years  experiment  in  which  unsprayed  checkrows  were  used. 
But  he  did  not  vary  the  frequency  between  plots  in  any  single  year.  There- 
fore, no  data  on  frequency  of  spraying,  of  any  value,  are  available  from  this 
source.  A  gain  in  yield  from  spraying,  ranging  from  7  to  83  bushels  per 
acre,  was  obtained  during  five  of  the  six  years.  Stone  did  not  attempt  to 
explain  the ,  one  year  of  loss  apparently  due  to  spraying,  altho  the  loss 
averaged  more  than  30  bushels  per  acre. 

Somewhat  conflicting  data  were  obtained  by  Sandsten  and  Milward 
(1906)  in  a  two-plot  experiment  of  one  year  duration.  Comparing  the 
results  from  two,  three,  five,  and  six  applications  of  bordeaux  to  each 
plot,  they  found,  on  one  plot,  a  constant  increase  in  yield  with  each  increased 
application  up  to  and  including  five,  the  increase  dropping  off  slightly 
with  six  applications.  The  second  plot  showed  a  general  tendency  for 
yields  to  increase  with  the  frequency  of  applications,  but  the  data  are 
inconsistent,  three  applications  resulting  in  a  yield  lower  than  that  of  'the 
check  plot,  while  five  applications  resulted  in  a  1,72-per-cent  increase. 

Testing  the  influence  of  frequency  of  spraying  on  yield  in  a  blight-free 
year,  Kohler  (1909)  compared  yields  from  plots  duplicated  four  times  and 
sprayed  two,  three,  four,  and  six  times,  respectively.  His  results  showed 
a  decrease  in  yield  of  marketable  tubers,  of  0.7  bushel  per  acre,  from 
spraying  two  times,  and  increased  yields  of  8.4,  15.8,  and  18.7  bushels  per 
acre,  respectively,  from  spraying  three,  four,  and  six  times,  as  compared 
to  check  plots.  A  year  later,  when  again  there  was  no  occurrence  of  blight, 
Kohler  (1910)  obtained  an  average  increase  in  yield  of  17.4  and  18.8 
bushels  per  acre  over  the  yields  of  the  unsprayed  plots,  from  four  and  six 
applications,  respectively.  Kohler  therefore  concluded  that,  irrespective 
of  late  blight,  better  yields  may  be  expected  from  sprayed  plots  because  of 
the  healthier  condition  of  the  foliage. 

The  value  of  thoroness  in  applying  bordeaux  has  been  well  demonstrated 
by  Zavitz  (1916)  in  his  report  of  a  seven-years  test  at  the  Ontario  station. 
In  five  of  the  seven  years,  no  blight  rot  occurred.  In  spite  of  this,  both 
total  and  marketable  yields  increased  directly  with  the  frequency  of 
spraying,  in  spraying  three,  four,  and  five  times  during  each  of  the  five 
years.  Zavitz  found  that  spraying  both  the  tops  and  the  bottoms  of  the 
plants  in  all  three  applications,  rather  than  spraying  only  the  tops,  gave 
an  increase  in  total  yield  of  13.5  bushels  per  acre,  thus  demonstrating  the 
value  of  thoroness.  In  1910,  a  year  of  blight  rot,  spraying  from  two  to 
six  times  gave  a  proportionate  increase  in  the  yield  of  sound  potatoes,  a 
constant  increase  in  the  length  of  the  growing  period  of  the  plants,  and  a 
constant  decrease  in  the  percentage  of  rot  in  the  crop. 


1258 


EARLE  V.  HARDENBURG 


Macoun  (1905)  did  not  test  the  influence  of  frequency  of  spraying,  but  by 
spraying  four  times  in  1901  and  in  1902,  and  five  times  in  1904,  he  obtained 
an  average  increased  yield,  for  the  three  years,  of  94.5  bushels  per  acre. 

In  spite  of  the  loss  of  millions  of  dollars  to  the  growers  in  New  York 
caused  by  the  occurrence  of  blight  every  two  or  three  years,  and  in  spite  of 
the  proved  value  of  bordeaux  mixture  as  a  preventive  of  this  disease,  rela- 
tively few  growers  make  a  practice  of  using  a  fungicide.  Altho  blight 
has  frequently  been  epiphytotic  in  all  four  of  the  regions  surveyed  except 
Franklin  and  Clinton  Counties,  only  one-third  of  the  growers  on  Long 
Island  in  1912,  5  per  cent  in  Steuben  County  in  1912,  and  25  per  cent 
in  Monroe  County  in  1913,  sprayed  their  crops  with  a  fungicide. 
Occasional  attacks  of  blight  have  been  observed  in  Franklin  and  Clin- 
ton Counties,  but  epiphyte  tics  are  practically  unknown;  and  even  when 
the  fungus  is  present  on  the  foliage,  it  seldom  attacks  the  tubers  to  any 
serious  extent  in  this  region.  Only  1  per  cent  of  the  growers  in  this  region 
sprayed  for  blight  prevention  in  1913.  So  few  growers  used  fungicide  in 
Steuben,  Monroe,  and  Franklin  and  Clinton  Counties,  that  the  influence  of 
frequency  on  yield  could  not  be  studied  in  detail.  The  extent  to  which 
insecticides  and  fungicides  were  used  in  the  four  regions,  and  the  average 
yields  per  acre  under  the  various  treatments,  are  given  in  table  83.  In 

TABLE  83.     SUMMARY  OF  SPRAYING  IN  THE  FOUR  REGIONS  SURVEYED 


Treatment 

Long  Island, 
1912 

Steuben  County, 
1912 

Monroe  County, 
1913 

Franklin  and 
Clinton  Counties, 
1913 

Per 
cent 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Per 
cent 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Per 

cent 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

Per 

cent 
of 
farms 

Average 
yield 
per  acre 
(bushels) 

No  spraying  
Insecticide  only  — 
Fungicide 

3 
64 
33 

190.7 
161.7 
197.1 

51 
44 
5 

130.2 
137.3 
171.5 

12 
63 
25 

150.3 
121.5 
126.2 

36 
63 
1 

186.1 
177.3 
152.3 

Average  

100 

175.5 

100 

136.4 

100 

126.2 

100 

179.3 

this  table,  a  reliable  criterion  of  the  beneficial  effects  of  spraying  with  fungi- 
cide is  not  evident  in  those  cases  in  which  the  percentage  of  growers 
following  any  one  of  the  three  practices  was  below  15. 

Spraying  on  Long  Island 

Spraying  was  done  to  a  greater  extent  on  Long  Island  than  in  the  other 
three  districts  surveyed.  Only  9  growers  out  of  316  did  not  spray  at  all  in 
1912.  About  one-third  of  all  the  growers  used  a  fungicide  for  the  control 
of  blight,  tipburn,  and  flea  beetles.  Ten  per  cent'of  the  growers  reported 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1259 


their  crops  affected  with  blight,  while  nearly  one-fourth  reported  flea- 
beetle  injury.  The  spraying  practices  and  the  average  yields,  together 
with  the  amount  of  seed  and  the  value  of  the  fertilizer  used,  are  given 
in  table  84.  The  number  of  growers  not  spraying  at  all  was  too  small 


TABLE  84. 


RELATION  OF  SPRAYING  PRACTICE  TO  YIELD  ON  316  LONG  ISLAND  FARMS  IN 
1912 


Spraying  practice 

Number 
of  farms 

Average 
yield 
per  acre 

(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

No  spraying  
Insecticide  only  

9 
204 

190.7 
161.7 

12.2 
11.8 

$33.08 
31.42 

Fungicide  

103 

197.1 

13.5 

33.65 

Total  

316 

Average  .  .      .    .        

175  3 

12.5 

$32  27 

to  allow  of  attaching  any  significance  to  the  average  yield  obtained  by 
these  growers.  The  increase  in  yield  per  acre  of  over  35  bushels,  resulting 
from  the  use  of  a  fungicide  rather  than  an  insecticide,  is  significant,  altho  a 
part  of  this  difference  in  yield  was  due  to  the  use  of  more  seed  and  fertilizer. 
Results  of  further  studies  on  the  influence  of  frequency  of  spraying  with 
fungicide,  on  yield,  are  shown  in  tables  85  and  86,  in  which  the  factors  of  seed 


TABLE  85. 


RELATION  OF  NUMBER  OF  TIMES  SPRAYED  WITH  FUNGICIDE,  AND  RATE  OF 
PLANTING,  TO  YIELD,  ON  109  LONG  ISLAND  FARMS  IN  1912 


Amount  of  seed  planted' 


Number  of  times 
sprayed 

Less  than  12 
bushels 

From  12  to  14 
bushels 

14  bushels  and 
more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 

(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  5 

11 
11 

4 

154.6 
197.2 
217.2 

15 
19 

8 

189.7 
196.5 
197.5 

7 
18 
16 

181.5 
197.0 
220.5 

33 

48 
28 

179.5 
196.9 
213.8 

5-7  

7  and  more  

Total  

26 

42 



41 

109 

Average  

187.5 

194.2 

.... 

201.6 

196.8 

1260 


EAELE  V.  HARDENBURG 


TABLE  86.      RELATION  OF  NUMBER  OP  TIMES  SPRAYED  WITH  FUNGICIDE,  AND  VALUE  OP 
MANURE  AND  FERTILIZER,  TO  YIELD,  ON  109  LONG  ISLAND  FARMS  IN  1912 


Number  of  times 
sprayed 

Value  of  murane  and  fertilizer 

Less  than  $30 

From  $30  to  $40 

$40  and  more 

Average 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Num- 
ber of 
farms 

Average 
yield 
per  acre 
(bushels) 

Less  than  5  

15 
13 
2 

161.4 
182.8 
170.0 

12 
25 

17 

177.9 
202.8 
191.3 

6 
10 
9 

236.3 

188.6 
248.6 

33 

48 

28 

179.5 
196.9 
213.8 

5-7  

7  and  more  

Total  

30 

54 

25 

109 

Average  .  . 

170.0 

195.4 

228.1 

196.8 

and  fertilizer,  respectively,  are  separated.  It  appears  from  table  85  that 
the  yield  increased  directly  with  the  frequency  of  spraying,  irrespective 
of  the  rate  of  planting.  In  table  86,  the  influence  of  frequency  of  spraying 
does  not  appear  to  have  been  so  marked.  This  is  due  partly,  however, 
to  the  insufficient  number  of  growers  in  some  of  the  groups.  As  a  whole, 
these  data  indicate  that  the  growers  who  sprayed  the  greatest  number  of 
times,  obtained  at  least  enough  increase  in  yield  to  pay  the  extra  cost 
of  the  labor  and  materials  involved.  The  correlation  of  frequency  of 
bordeaux  spraying  with  yield  is  further  shown  in  figure  149.  The  coeffi- 


Yield  per  acre,  in  bushels 

rH  T— I  i— I  i— I  C^  C^ 
CO  i-H  CO  '— I  CO  T— I 
^  2  SH  i2  ^H  ^ 


IO  O 

t^  ^i 

C^  CO 

T— I  CO         '— I 

oq  c^    co 


'-£  o 


0,-pH 

1 


10 


1        1        1 

2 

1 

1 

7 

2 

3 

5 

1 

2 

1 

14 

1                     3 

2 

4 

10 

1                                1 

3 

4 

3 

3 

1 

16 

1                     3 

3 

4 

3 

2 

1 

2        1 

20 

1                     5 

2 

5 

2 

4 

2 

21 

1 

2 

3 

1 

7 

1                     1 

1 

2 

2 

1 

8 

0 

1 

1 

2 



0 


11        6 


3     1 


FIG.  149. 


5          2         16         18        27         11 
r  =  0.133  ±0.065 

CORRELATION  OF  FREQUENCY  OF  BORDEAUX  SPRAYING,   AND   YIELD,   ON    105   LOI 
ISLAND  FARMS  IN  1912 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1261 


cient,  0.133  ±  0.065,  while  positive,  is  not  significant  because  of  the 
relatively  high  probable  error.  Since  all  factors  influencing  yield  are 
involved  in  this  correlation,  such  a  coefficient  need  not  detract  from  the 
real  measure  of  efficiency  of  bordeaux  spraying.  Much  of  interest  regard- 
ing the  actual  practice  of  spraying  thruout  the  region  may  be  observed 
in  the  frequency  table  shown  in  figure  149. 

Spraying  in  Steuben  County 

The  year  1912  was  a  year  of  blight  epiphytotic  in  Steuben  County,  many 
of  the  growers  reporting  more  than  half  their  crop  left  rotted  and  un- 
harvested  in  the  field.  More  than  93  per  cent  of  the  growers  found  that 
the  late-blight  fungus  affected  either  tops  or  tubers,  or  both.  Such  con- 
ditions should  afford  excellent  means  for  determining  the  influence  of 
frequency  of  bordeaux  spraying  on  yield.  The  practice  of  spraying  in 
this  region  in  1912,  the  average  yield,  the  rate  of  planting,  and  the  value 
of  manure  and  fertilizer  per  acre,  are  shown  in  table  87.  The  two  facts 

TABLE  87.    RELATION  OF  FPRAYING  PRACTICE  TO  YIELD  ON  360  STEUBEN  COUNTY  FARMS 

IN  1912 


Spraying  practice 

Number 
of 
farms 

Average 
yield 
per 

acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

No  spraying  

184 

130  2 

9  9 

$  9  97 

Insecticide  only  

160 

137  3 

10  2 

10  23 

Fungicide  

16 

171  5 

11  5 

12  96 

Total  

360 

Average  .  . 

136  4 

10  1 

$10  06 

most  clearly  set  forth  in  this  table  are:  .(1)  that,  whereas  less  than  half 
the  growers  of  this  region  did  any  spraying  in  1912,  only  about  4.5  per 
cent  used  a  fungicide  for  blight  control;  and  (2)  that  those  growers  who 
sprayed  the  most  thoroly  also  used  more  seed  and  fertilizer  per  acre  than 
the  average,  and  obtained  correspondingly  higher  yields. 

Spraying  in  Monroe  County 

The  treatment  accorded  the  potato  crop  for  blight,  tipburn,  and  flea- 
beetle  control  in  Monroe  County  in  1913  is  shown  in  table  88.  These 
data  indicate  no  advantage  whatever,  as  to  yield,  from  fungicidal  spraying 
in  1913.  Evidently  there  was  none.  The  explanation  doubtless  lies  in 
the  fact  that  the  principal  functions  of  bordeaux  mixture  lie  in  the  protec- 
tion of  the  tubers  from  blight  rot  and  in  the  prolongation  of  the  plant's 


1262 


EARLE  V.  HARDENBURG 


TABLE  88. 


RELATION  OF  SPRAYING  PRACTICE  TO  YIELD  ON  282  MONROE  COUNTY  FARMS 
IN  1913 


Spraying  practice 

Number 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

No  spraying  

33 

150  3 

12  2 

$11  40 

Insecticide  only  

177 

121  5 

12  2 

11  07 

Fungicide  

72 

126  2 

13  3 

11  90 

Total  

282 

Average 

126  0 

12  5 

$11  33 

growing  season,  thereby  increasing  yield.  The  latter  function  naturally 
is  asserted  late  in  the  growing  season.  In  1913,  Monroe  County  ex- 
perienced one  of  the  earliest  killing  fall  frosts  in  its  history.  As  a  result, 
not  only  the  bean  crop,  but  the  potato  crop  as  well,  was  cut  down,  causing 
serious  loss  to  the  grower.  Only  about  7  per  cent  of  the  potato  growers 
reported  the  occurrence  of  late  blight  up  to  the  time  of  this  frost.  It  is 
therefore  evident  that  the  possible  advantages  from  fungicidal  spraying  this 
year  were  almost  entirely  nullified.  Under  these  conditions,  frequency  of 
spraying  could  not -be  expected  to  show  a  normal  influence  on  yield.  The 
correlation  coefficient  (fig.  150)  is  0.084  ±  0.081.  This  shows  insignificant 
correlation  in  respect  to  both  the  coefficient  and  its  probable  error. 


Yield  per  acre,  in  bushels 

8  8  8  S  I 


^  ci  ri<  Ci  JH 

S      S      S      £      8 


i 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 


4 

3 

3 

4 

1        1 

3 

8 

1 

4 

1        1                 1 

1 

3 

2 

4 

3        1 

1 

2 

1 

3 

4 

1 

1 

2 

1 

1 

1 

1 

11 


0 


16 

19 

14 

11 

4 

2 

1 

0 

0 

0 

0 

1 

68 


18   7   17   11   3 
r  =  0.084  ±  0.081 

FlG.    150.       CORRELATION   OF  FREQUENCY  OF  BORDEAUX  SPRAYING,  AND  YIELD,  ON  68  MONROE 

COUNTY  FARMS  IN  1913 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1263 


Spraying  in  Franklin  and  Clinton  Counties 

As  previously  stated,  the  late-blight  fungus  (Phytophthora  infeitans) 
seldom  attacks  the  potato  crop  in  Franklin  and  Clinton  Counties.  Very 
probably  the  reason  for  this  is  that  muggy  atmospheric  conditions, 
so  conducive  to  the  disease,  seldom  prevail  here  after  rains.  On  the 
contrary,  wide  spacing  of  plants  and  the  frequent  breeze  that  follows 
rain  afford  the  plants  ideal  air  circulation,  thus  preventing  conditions 
favorable  to  blight.  Only  3  per  cent  of  the  growers  reported  blight  in 
1913. 

The  extent  to  which  spraying  is  practiced  in  this  region  is  shown  in  table 
89.  Altho  the  three  growers  who  used  fungicide  used  more  than  the 

TABLE  89.    RELATION  OF  SPRAYING  PRACTICE  TO  YIELD  ON  273  FRANKLIN  AND  CLINTON 

COUNTY  FARMS  IN  1913 


Spraying  practice 

Number 
of 
farms 

Average 
yield 
per 
acre 
(bushels) 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure 
and 
fertilizer 

No  spraying  
Insecticide  only  
Fungicide  

98 
172 
3 

186.1 
177.3 
152.3 

12.1 
11.8 
12.3 

$12.59 
13.29 
15.38 

Total  

273 

Average  . 

179  9 

11.9 

$13  08 

average  quantity  of  seed  and  fertilizer,  they  obtained  less  than  the  average 
yield.  However,  no  significance  can  be  attached  to  this  fact,  because  of 
the  extremely  small  number  of  farms.  For  this  same  reason,  no  correla- 
tion study  of  the  frequency  of  spraying  with  .the  yield  in  this  region  has 
been  made. 

RELATION  OF  DATE  OF  HARVEST  TO  YIELD 

The  date  of  harvest  of  the  potato  crop  is  dependent  on  such  factors  as 
(1)  the  date  of  maturity  of  the  crop,  (2)  the  date  of  the  first  killing  frost 
in  the  region,  (3)  the  influence  of  early  market  prices,  (4)  the  relation  of 
the  potato  harvest  to  other  farm  work,  and  (5)  the  weather.  The  relative 
importance  of  each  of  these  factors  varies  with  the  region,  in  New  York 
State.  There  are  sufficient  experimental  data  available  to  prove  that 
ordinarily  the  crop  should  not  be  harvested  until  the  foliage  is  entirely 
dead  because  of  natural  maturity.  The  basis  of  this  proof  lies  in  the  fact 
that  the  yield  is  increased  rapidly  during  the  last  stages  of  growth  of  the 
plant.  Jones  (1899)  tested  the  influence  of  the  date  of  harvest  on  the  yield 


1264 


EARLE  V.  HARDENBURG 


of  potatoes  planted  on  May  20,  by  digging  every  ten  days  from  August 
2  to  September  22.  The  yield  increased  from  30  bushels  per  acre  on  August 
2,  to  353  bushels  per  acre  on  September  22.  Of  this  increase,  119  bushels 
came  after  September  1,  and  50  bushels  developed  during  the  last  ten  days. 
Kohler  (1910),  working  with  the  variety  Early  Ohio  planted  on  June  3, 
similarly  tested  the  rapidity  of  development  of  the  yield  by  digging  about 
every  seven  days  from  July  31  to  August  30.  During  that  period,  the 
foliage  developed  from  an  entirely  green  condition  to  complete  maturity, 
and  the  marketable  yield  increased  from  10.9  bushels  to  226.8  bushels 
per  acre.  There  was  a  gain  in  marketable  yield  of  about  7  bushels  a  day 
thruout  the  period,  the  yield  increasing  44.7  bushels  per  acre  during  the 
last  week.  These  data  emphasize  the  possible  mistake  which  some  grow- 
ers make,  of  digging  the  crop  prior  to  maturity  in  order  to  avoid  unfavor- 
able weather  or  to  take  advantage  of  the  relatively  high  early-market 
prices. 

It  was  not  possible,  for  four  reasons,  to  study  by  survey  methods  the 
influence  of  date  of  harvest  on  yield  in  the  four  regions  surveyed.  First, 
the  information  concerning  the  date  of  harvesting  for  Long  Island  was 
insufficient;  secondly,  about  93  per  cent  of  the  growers  in  Steuben  County 
reported  the  crop  more  or  less  affected  with  late  blight;  thirdly,  a  large 
proportion  of  the  growers  in  Monroe  County  reported  a  killing  frost  in 
1913  which  cut  down  their  crop  exceptionally  early,  long  before  maturity, 
and  reduced  the  yield  much  below  the  average;  and  fourthly,  in  Franklin 
and  Clinton  Counties  the  foliage  is  almost  always  killed  by  frost  before 
it  is  mature,  as  was  the  case  in  1913.  The  average  date  of  harvest  in 
the  four  regions  for  the  years  concerned  in  the  survey,  and  the  average 
date  of  the  first  killing  fall  frost  for  each  region,  are  given  in  table  90: 

TABLE  90.    AVERAGE  DATE  OF  HARVEST,  AND  AVERAGE  DATE  OF  FIRST  KILLING  FROST, 
IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Year 

Number 
of 
farms 

Average 
date  of 
harvest 

Average  date 
of  first  killing 
f  all  frost 

Long  Island  

1912 

37 

September  1 

October  1-25 

Steuben  County  

1912 

348 

September  27 

October  5 

Monroe  County  . 

1913 

269 

October  12 

October  15 

Franklin  and  Clinton  Counties  

1913 

295 

September  24 

October  1-10 

As  is  seen  in  table  90,  the  Long  Island  crop  was  harvested  nearly  a 
month  before  that  of  any  of  the  other  regions,  the  average  date  of  planting 
being  correspondingly  earlier  in  this  region  due  to  climatic  conditions. 
With  the  exception  of  Irish  Cobbler  and  other  early  varieties  grown  in 
Nassau  County,  the  crop  in  this  district  is  usually  mature  before  it  is 
dug.  These  early  varieties  are  often  harvested  and  marketed  before 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIFLD  OF  POTATOES     1265 

maturity  in  order  to  reap  the  benefit  of  the  early-market  prices.  Further- 
more, growers  of  early  varieties  in  Nassau  County  harvest  early  in  order 
to  be  able  to  follow  the  potato  crop  with  a  crop  of  vegetables  or  root  crops 
for  the  fall  market.  A  harvest  of  Cobbler  potatoes  in  Nassau  County, 
in  the  middle  of  July,  is  shown  in  figure  130  (page  1152).  It  can  be  noted 
that  the  foliage,  as  separated  from  the  tubers,  is  not  yet  mature.  On  the 
following  day  this  same  field  was  ridged  for  turnip  planting. 

As  is  evident  from  table  90,  the  Long  Island  crop  is  seldom  affected  by 
a  killing  fall  frost.  The  Long  Island  growers  aim  to  market  their  crop 
as  soon  after  maturity  as  is  possible,  in  order  to  supply  the  New  York 
City  market  before  the  earliest  crop  of  other  sections  of  the  State  is  ready 
to  harvest.  For  the  years  concerned  in  this  study,  the  crop  in  the  other 
three  regions  was  harvested  at  an  average  date  earlier  than  the  average 
date  of  the  first  fall  frost  because  of  the  severe  blight  epidemic  of  Steuben 
County,  the  early  and  severe  frost  in  Monroe  County,  and  the  early 
frost  in  Franklin  and  Clinton  Counties.  Partly  because  of  the  tempering 
influence  of  Lake  Ontario,  the  average  date  of  harvest  and  the  average 
date  of  the  first  fall  frost  in  Monroe  County  are  considerably  later  than 
for  the  other  regions.  Similarly,  because  of  the  influence  of  Lake  Cham- 
plain,  the  growers  located  around  Peru,  in  Clinton  County,  harvested  their 
1913  crop  approximately  two  weeks  later  than  did  other  growers  in  the 
county. 

METHOD  OF  HARVESTING  IN  THE  FOUR  REGIONS  SURVEYED 

The  factors  that  ordinarily  determine  whether  potatoes  shall  be  dug 
by  hand  or  by  machine  are,  size  of  acreage,  available  labor  supply,  and  soil 
conditions  affecting  the  efficiency  of  machine  diggers.  The  author  (Har- 
denburg,  1915  a)  found,  for  Steuben  County  in  1912,  that  when  the 
potato  acreage  per  farm  was  at  least  5,  the  saving  in  labor  cost  by  machine 
digging  more  than  outweighed  the  interest,  depreciation,  and  repair  costs 
of  digging  by  this  method.  Since  the  minimum  acreage  of  potatoes  per 
farm  recorded  in  these  studies  was  5,  the  factor  of  economy  in  the  use  of 
machines  for  digging  is  probably  of  no  concern  in  any  of  the  other  three 
regions.  There  are  many  farms  in  Steuben  County  with  fields  so  steep 
as  to  limit  the  use  of  heavy  elevator  diggers.  In  1912  the  writer  (Harden- 
burg,  1915  a)  found  the  average  slope  of  potato  fields  dug  by  hand  to  be 
somewhat  steeper  than  that  of  machine-dug  fields.  A  special  type  of 
digger,  known  as  the  Boss,  or  Keeler,  which  removes  the  tubers  by  a  rotating 
reel,  has  been  adapted  to  the  hilly  sections  of  Steuben  County  because  of 
ite  exceptionally  light  draft  and  its  adaptation  to  slopes  too  steep  for  elevator 
diggers.  A  study  of  the  influence  of  slope  of  field  on  the  type  of  digger 
used  in  1912  in  Steuben  County  rqvealed  the  fact  that  the  fields  dug  with 
the  reel  digger  had  a  higher  average  slope  than  those  dug  with  the  elevator 
type  (Hardenburg,  1915  a). 


1266 


EARLE  V.  HARDENBURG 


The  method  of  harvesting,  and  the  average  potato  acreage  per  farm,  for 
the  four  regions  surveyed,  is  shown  in  table  91.     It  is  evident  that  the 


TABLE  91. 


METHOD  OF  HARVESTING,  AND  AVERAGE  POTATO  ACREAGE  PER  FARM,  IN 
THE  FOUR  REGIONS  SURVEYED 


Method  of 
harvesting 

Long  Island, 
1912 

Steuben 
County,   1912 

Monroe 
County,    1913 

Franklin  and 
Clinton 
Counties,  1913 

Per 

cent 
of 
farms 

Average 
potato 
acreage 

Per 

cent 
of 
farms 

Average 
potato 
acreage 

Per 

cent 
of 
farms 

Average 
potato 
acreage 

Per 

cent 
of 
farms 

Average 
potato 
acreage 

Elevator  digger  
Reel  digger  
Shovel  plow  shaker 
Hand 

84 
5 
5 
1 
5 

24.3 
21.8 
19.1 
41.6 

11 
48 
12 
23 
6 

17.0 
14.9 
13.4 
15.4 

71 
0 
11 
3 
"15 

12.9 

"i6y 

9.2 

15 
1 
0 
76 

8 

8.0 
7.5 

6.9 

Various 

Average  

24.8 

.... 

14.7 

12.4 

7.2 

reel  digger  is  not  popular  outside  of  Steuben  County,  probably  decause  this 
digger  leaves  the  tubers  in  a  more  or  less  bruised  and  scattered  condition. 
As  indicated  by  the  figures  for  both  Long  Island  and  Monroe  County, 
the  elevator  digger  was  used  extensively  in  these  regions,  where  the  soil 
is  relatively  light  and  the  fields  vary  from  rolling  to  level.  Growers  in 
Franklin  and  Clinton  Counties  have  not  used  the  elevator  digger  exten- 
sively because  of  relatively  small  acreages  per  farm  and  an  abundance 
of  large  boulders,  which  make  the  use  of  such  a  digger  next  to  impossible. 
More  than  three-fourths  of  the  crop  in  this  region  was  dug  by  hand 
in  1913. 

As  a  whole,  the  figures  in  table  91  show  that  the  average  acreage  dug  by 
hand  was  smaller  than  that  dug  by  machine,  and  that  the  average  acreage 
dug  by  the  elevator  digger  was  greater  than  that  dug  by  any  other  type 
of  machine.  In  cases  of  close  planting  and  heavy  top  growth,  it  is  often 
desirable  to  remove  the  tops  from  the  tubers  before  picking  them  up. 
In  figure  151,  a  view  taken  in  Franklin  County,  two  men  are  shown  using 
forks  for  this  purpose,  behind  an  elevator  digger  drawn  by  four  horses. 
This  illustrates  the  necessity  of  using  more  than  two  horses  because  of 
the  heavy  draft  of  these  machines. 

Three  types  of  carriers  were  found  in  common  use  in  the  regions  visited  — 
the  standard  bushel  slatted  crate,  a  hamper  basket,  and  fertilizer  bags 
of  various  sizes.  On  Long  Island,  the  commonest  carrier  in  Suffolk 
County  is  the  fertilizer  bag,  and  that  in  Nassau  County  is  the  fertilizer 
bag  supplemented  by  hamper  baskets  of  about  a  bushel  capacity.  These 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1267 


FlG.    151.      REMOVING   VINES   FROM   TUBERS   TO    FACILITATE    PICKING   UP   THE    CROP 

hampers  as  used  in  Nassau  County,  with  the  owner's  initial  painted  on 
them,  are  shown  in  figure  152.  This  illustration  shows  also  the  common 
practice  in  this  region  of  throwing  from  three  to  five  rows  together  before 
picking  up  the  tubers.  The  prime  tubers  are  then  picked  up  first,  the 
culls  remaining  until  later,  as  illustrated.  Most  of  the  crop  of  Nassau 
County  —  which  is  marketed  directly  from  the  field  —  is  taken,  either  in 
these  baskets  or  in  bags,  by  wagon  or  motor  truck,  to  the  Wallabout 
Markets  of  Brooklyn,  as  shown  in  figure  153.  In  Suffolk  County  the  crop 
is  taken  from  the  field  mainly  in  bags  and  is  hauled  in  them  to  the  car  or 
the  storehouse,  where  the  potatoes  are  dumped  on  the  grader  if  they  were 
not  already  graded  when  they  were  picked  up,  and  are  thence  emptied 
into  the  car  for  shipment  in  bulk. 

The  commonest  carrier  used  in  the  other  three  regions  is  the  bushel 
crate,  in  which  the  crop  is  taken  to  storage,  and  there  it  is  either  dumped 
into  piles  or  stored  in  the  crate.  By  far  the  greater  part  of  the  crop  is 
stored  in  bulk.  In  these  three  regions,  the  crop  is  taken  to  the  car  either 
loose  in  wagon  boxes,  or  in  bags,  or  both  ways,  with  the  bags  piled  on  top 
of  the  load. 


1268 


EARLE  V.  HARDENBURQ 


FlG.    152.      THE   BUSHEL   HAMPERS    COMMONLY    USED   FOR  BOTH    PICKING  UP  AND  HAULING   TO 

MARKET  IN   NASSAU    COUNTY 


FlG.  153.     A  NASSAU  COUNTY  ROAD  WAGON,  LOADED  FOR  THE  WALLABOUT  MARKETS  OF  BROOKLYN 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES  1269 

TYPES   OF   STORAGE    IN  THE   FOUR   REGIONS    SURVEYED 

Since  Appleman  (1912)  has  shown  the  importance  of  low  temperature 
in  proper  potato  storage,  it  is  of  interest  to  note  the  types  of  storage  used  for 
the  crops  concerned  in  these  studies.  In  no  case  was  any  grower's  crop 
kept  in  a  refrigerated  storage.  The  proportion  of  the  total  stored  crop  in 
each  region  which  was  stored  in  various  types  of  storage  facilities  is  given 
in  table  92.  The  reason  for  the  larger  number  of  farms  indicated  in  Steuben 

TABLE  92.     TYPES  OF  POTATO  STORAGE  IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Number 
of 
farms 

Per  cent  of  stored  crop  stored  in 

House 
cellar 

Barn 
cellar 

Special 
storage 

Barn 
shed 

Pit 

storage 

Long  Island,  1912     . 

231 
378 
320 

300 

61 

85 

72 

98 

22 
11 
24 

1 

12 
3 
3 

1 

3 
0 
0 

0 

2 
1 
1 

0    * 

Steuben  County   1912 

Monroe  County,  1913  

Franklin    and    Clinton    Counties, 
1913  

and  Monroe  Counties  than  were  actually  visited  in  the  survey,  is  due  to 
the  fact  that  a  number  of  the  growers  in  these  regions  stored  their  crop  in 
more  than  one  type  of  storage. 

Practically  all  of  the  Franklin  and  Clinton  County  crop  of  1913  was  stored 
in  the  house  cellar.  In  fact,  this  was  the  principal  type  of  storage,  tho 
to  a  lesser  extent,  in  the  other  regions  studied.  The  next  most  popular 
type  of  storage  was  the  barn  cellar.  As  a  rule,  both  house  and  barn 
cellars  were  constructed  with  stone  walls  and  dirt  floors.  Wherever  a  barn 
cellar  was  used,  it  was  generally  in  close  proximity  to  the  stable,  advantage 
being  thus  taken  of  the  animal  heat  therefrom  to  prevent  freezing.  This 
was  not  considered  a  safe  practice  in  Franklin  and  Clinton  Counties  because 
of  the  greater  severity  of  the  winters  in  that  region.  A  number  of  special 
storage  houses  were  found  on  Long  Island.  Since  only  a  small  proportion 
of  the  Long  Island  crop  is  held  for.  more  than  a  few  days,  these  special 
storages  were  built  not  so  much  to  store  the  harvested  crop  as  for  a  place 
of  storage  for  the  seed  .supply  brought  in  from  the  North  to  be  held  until 
planting  time. 

LENGTH    OF  STORAGE   PERIOD 

In  determining  the  length  of  time  that  the  crop  was  held  by  the  growers 
in  each  region,  the  actual  date  of  sale  of  all  or  of  parts  of  the  crop  was  taken 
as  an  indicator  of  the  storage  period.  It  was  found  that  a  large  part  of 
the  crop  in  all  four  regions  was  marketed  either  directly  from  the  field,  or 


1270 


EARLE  V.  HARDENBURG 


after  only  a  few  days  of  holding  for  proper  grading  and  bagging  at  the 
barn.  In  table  93,  the  proportion  of  the  crop  so  handled  is  considered  as 
not  stored. 

TABLE  93.     LENGTH  OF  STORAGE  PERIOD  IN  THE  FOUR  REGIONS  SURVEYED 


Region 

Per  cent  of  crop  stored 

None 

For 
one 
month 

For 
two 
months 

For 

three 
months 

For 

four 
months 

For 

five 
months 

For 
six 

months 

For 

seven 
months 

Long  Island,  1912. 
Steuben  County, 
1912  
Monroe  County, 
1913  
Franklin  and  Clin- 
ton      Counties, 
1913  

88 
64 
38 

42 

5 
6 
3 

1 

0 
12 
11 

12 

3 
6 
21 

21 

2 

8 
11 

17 

1 
3 
10 

1 

0 
1 
5 

5 

1 
0 

1 

1 

As  is  indicated  in  table  93,  a  larger  proportion  of  the  crop  is  stored  for 
one  or  more  months  in  the  three  regions  of  western  and  northern  New  York 
than  on  Long  Island.  Except  on  Long  Island,  the  general  practice  is  to 
market  at  least  that  part  of  the  crop  for  which  there  is  insufficient  storage 
capacity,  at  harvest  time,  the  remainder  being  disposed  of  as  prices  warrant 
and  as  weather  and  country  roads  permit.  Much  of  the  crop  in  Steuben 
County  is  grown  under  contract  for  local  buyers.  The  grower's  delivery 
of  this  crop  mainly  at  harvest  time  accounts  for  the  relatively  high  propor- 
tion of  the  crop  not  stored  in  this  region. 

SUMMARY 

Climate,  elevation,  and  soil,  as  factors  influencing  yield,  were  found  by 
this  study  to  be  so  closely  and  inseparably  related  as  to  make  difficult  the 
determination  of  the  influence  of  each  one.  The  study  of  available  data 
shows  that,  whereas  the  climate  for  potatoes  is  generally  best  at  the 
highest  elevations,  soil  fertility  is  generally  the  greatest  at  the  lower  eleva- 
tions. In  a  year  of  blight,  farms  at  high  elevations  are  likely  to  show  the 
best  yields;  while  in  years  of  no  blight,  better  yields  may  be  expected  from 
the  more  fertile  soils  at  the  lower  elevations. 

The  value  of  potato  land  as  appraised  by  the  growers,  proved  to  be  corre- 
lated with  yield  up  to  the  point  at  which  the  land  was  affected  by  real -estate 
valuation.  This  point  was  reached  for  a  few  farms  located  in  close  proxim- 
ity to  cities  or  villages.  The  appraised  valuation  of  these  farms  was 
evidently  beyond  the  valuation  justified  by  their  productive  ability. 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1271 

From  information  obtained  in  the  survey  of  the  four  regions,  it  has  been 
possible  to  determine  the  status  of  many  factors  which,  tho  not  studied  as 
to  their  influence  on  yield,  have  nevertheless  a  vital  relation  to  production. 
Among  these  may  be  listed  the  time  of  plowing,  the  home-mixing  of 
fertilizer,  the  analysis  of  fertilizer,  the  use  of  lime,  the  source  of  seed,  the 
chemical  treatment  of  seed,  the  date  of  planting,  the  method  of  planting, 
the  date  and  method  of  harvesting,  the  type  of  storage,  and  the  length  of 
the  storage  period. 

Both  biometrical  and  tabulation  studies  have  shown  the  amount  of  seed 
used  and  the  value  of  manure  and  fertilizer  per  acre  to  be  the  most  influen- 
tial factors  as  relating  to  yield  of  all  the  factors  studied.  Second  to  these 
are  depth  of  plowing,  frequency  of  cultivation,  and  frequency  of  spraying. 
The  influence  of  these  five  factors,  expressed  biometrically  in  terms*  of  r, 
is  summarized  for  each  region  in  table  94.  For  obvious  reasons,  based 

TABLE  94.    SUMMARY   or  COEFFICIENTS  OF  CORRELATION  FOR  FIVE  FACTORS  IN  THE 

REGIONS  SURVEYED 


Factor 

Long  Island, 
1912 

Steuben  County, 
1912 

Monroe  County, 
1913 

Franklin  and 
Clinton  Counties, 
1913 

Depth  of  plowing 
Value   of   manure 
and  fertilizer.  .  . 
Bushels  •  of  __  seed 
used.  
Frequency  ^of  cul- 
tivation   
Frequency  of  bor- 
deaux spraying 

r  =  0.159  ±  0.036 
r  =  0.244  ±  0.035 
r  =  0.275  ±  0.034 
r  =  -0.087  ±  0.037 
r  ='0.133"±  0065 

r  =  0.190  ±  0.034 
r  =  0.289  ±  0  033 
r  =  0.374  ±  0.031 
r  =  0.231  ±  0.034 

r  =  0.qp6  ±0.039 
r  =  0.258  ±  0.036 
r  =  0.247  ±  0.037 
r  =  0.169  ±  0.038 
r  —  0  084  ±  0  081 

r  =  0.028  ±  0.039 
r  =  0.169  ±  0.038 
r  ==  0.367  ±  0.034 
r  =  0.055  ±  0.039 

chiefly  on  environmental  differences  between  the  four  regions,  consider- 
able variation  in  the  value  of  coefficients  is  shown  in  the  table.  In  a  single 
case,  that  for  frequency  of  cultivation  on  Long  Island,  the  coefficient  is 
negative.  Five  coefficients  out  of  the  eighteen  given  are  too  small  to  be 
significant,  the  probable  reasons  for  this  being,  in  most  cases,  explained  in 
the  foregoing  text.  In  but  two  cases  is  the  probable  error  greater  than 
the  coefficient,  these  being  the  probable  errors  of  the  coefficients  for  depth 
of  plowing  in  Monroe  County  and  in  Franklin  and  Clinton  Counties. 

Probably  a  more  reliable  measure  of  the  true  influence  of  these  five 
factors  on  yield  may  be  obtained  from  the  tabulation  studies  for  each 
region.  In  view  of  the  proved  importance  of  these  factors,  a  compari- 
son of  the  averages  of  some  of  them  for  the  fifty  highest-  and  the  fifty 
lowest-yielding  farms  in  the  four  regions  is  given  in  table  95.  In  general, 
the  values  given  in  this  table  confirm  the  results  shown  in  the  discussion 
of  these  factors. 


1272 


EARLE  V.  HARDENBURG 


TABLE  95.  COMPARISON  OF  FIFTY  HIGHEST-  AND  FIFTY  LOWEST- YIELDING  FARMS  OF  THE 
FOUR  REGIONS  SURVEYED,  IN  AVERAGE  YIELD,  POTATO  ACREAGE,  SEED  USED,  AND 
FERTILIZER  USED,  AND  PERCENTAGE  OF  GROWERS  SPRAYING  WITH  FUNGICIDE 


Region 

0 

Average 
yield 
per  acre 
(bushels) 

Average 
potato 
acreage 
per  farm 

Average 
amount  of 
seed  used 
per  acre 
(bushels) 

Average 
value  of 
manure  and 
fertilizer 

Per  cent  of 
growers 
spraying 
with 
fungicide 

High- 
est 

Low- 
est 

High- 
est 

Low- 
est 

High- 
est 

Low- 
est 

High- 
est 

Low- 
est 

High- 
est 

Low- 
est 

Long  Island,  1912.  . 
Steuben  County, 
1912  

254.6 
204.6 
205.1 

247.8 

95.6 
72.4 
64.0 

114.8 

29.8 
15.1 
13.2 

7.0 

18.2 
12.0 
12.8 

7.5 

13.6 
11.2 
13.6 

13.6 

11.6 
9.0 
11.7 

10.7 

$35.35 
13.65 
14.12 

15.09 

$29.56 

7.78 
9.08 

11.78 

50 
16 
20 

0 

16 
0 
22 

2 

Monroe  Count  y, 
1913  
Franklin  and  Clin- 
t  o  n      Counties, 
1913 

Factors  of  less,  but  by  no  means  negligible,  influence  on  yield,  as 
developed  by  these  survey  studies,  are:  method  of  applying  fertilizer, 
varietal  type  of  potatoes,  sun-sprouting  of  seed,  interval  between  cutting 
seed  and  planting*  dusting  cut  seed,  type  of  seed,  system  of  planting, 

depth  of  planting,  system  of  cultivation. 

• 

CONCLUSIONS 

The  foregoing  study  of  crop  production  by  survey  methods  has,  wholly 
apart  from  the  facts  brought  out,  shown  the  broad  possibilities  of  this 
method  of  research.  It  does  have  limitations,  however,  as  is  evidenced 
by'  certain  conflicting  data  and  by  the  occasionally  inconclusive  results 
reported  herein.  It  cannot  be  used  as  a  substitute  either  for  the  present 
carefully  executed  research  of  the  state  and  federal  experiment  stations, 
or  for  more  generally  localized  controlled  experiments.  On  the  basis  of 
facts  and  indications  revealed  in  this  study,  however,  the  survey  method 
can  and  should  play  a  more  prominent  part  in  supplementing  the  present 
scope  of  research.  In  general,  too  much  emphasis  has  been  placed  on 
conclusions  drawn  from  limited  experimentation  without  due  attention 
to  their  application  to  local  conditions.  Too  little  research  of  regional 
application  has  been  done.  Cooperative  experiments  have  been  tried, 
but  they  have  not  been  sufficiently  extensive  in  duration. 

A  crop  survey,  to  be  of  greatest  value,  should  be  replicated  in  a  given 
region,  depending  on  the  normality  of  seasonal  conditions.  The  year 
1912,  while  possibly  normal  for  Long  Island,  was  a  year  of  severe  loss 
from  blight  to  the  potato  crop  in  Steuben  County.  The  year  1913,  while 
possibly  normal  for  Franklin  and  Clinton  Counties,  was  a  year  with  an 
extraordinarily  early  killing  fall  frost  in  Monroe  County.  These  factors 
have  doubtless  vitiated  to  some  degree  the  results  of  the  present  study 


A  STUDY  OF  FACTORS  INFLUENCING  THE  YIELD  OF  POTATOES     1273 

of  the  influence  of  certain  factors  on  yield.  A  larger  number  of  records 
for  each  region,  and  replication  of  the  survey,  may  be  suggested  as  the 
best  and  probably  the  only  means  of  obviating  these  conditions.  Whereas 
sufficient  records  were  not  available  for  the  detailed  study  of  some  factors, 
the  number  used  has,  on  the  whole,  afforded  means  for  fairly  definite 
conclusions.  For  as  extensive  a  study  of  details  as  has  been  pursued  in 
the  present  investigations,  not  less  than  three  hundred,  and  preferably 
four  hundred,  records  should  be  used.  Aside  from  the  relative  influence 
of  various  factors  on  yield  as  revealed  in  these  studies,  it  has  been  possible 
to  correct,  as  well  as  to  verify,  many  popular  ideas  of  long  standing.  Altho 
the  "  what,"  the  "  why,"  and  the  "  how  "  of  crop  production  have  for 
years  been  projected  to  the  farmer,  the  regional  study  of  actual  cause 
and  effect  by  survey  methods  has  at  least  contributed  to  the  knowledge 
as  to  the  "  how  much." 

AUTHOR'S  ACKNOWLEDGMENT 

The  writer  wishes  to  make  acknowledgment  of  the  help  given  him  by 
Professor  E.  G.  Montgomery,  under  whose  direction  this  investigation 
was  made,  and  to  express  appreciation  to  Messrs.  D.  S.  Fox,  W.  M. 
Peacock,  M.  F.  Abell,  R.  F.  Pollard,  and  R.  H.  Cross,  who  assisted  in  the 
taking  of  records.  Grateful  acknowledgment  is  made  also  to  the  many 
farmers  who  furnished  the  information  necessary,  and  to  Miss  Nellie  Van 
Dyne  for  her  capable  assistance  in  the  compilation  of  the  data. 


1274  EARLE  V.  HARDENBURG 


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Memoir  52,  Studies  in  Pollen,  with  Special  Reference  to  Longevity,  the  fifth  precedes:  number  in  this  series 
of  publications,  was  mailed  on  March  9,  1922. 


NEW  YORK  STATE  COLLEGE  OF  AGRICULTURE 

CORNELL  UNIVERSITY,  ITHACA,  N.  Y. 
DEPARTMENT  OF  FARM  PRACTICE  AND  FARM  CROPS 

Farm  No Potato  Record  for  1912..    Date , 1913 

Operator Age P.  O County 

Location Miles  to  shipping  point Soil  types Elevation 

Topography  of  farm Drainage Exposure  1912 

Acres  farmed Value  of  land  per  acre ....Acres  potatoes -1912 

Tenure _ Years  owner Years  renter 

Rotation  1 .2 3 4 5 : 6 

CROP  PRODUCTION  FOR  1912 


Crop 

Acres 

Yield  per  acre 

Total 

Corn,  grain...  
Com  silage 



tons 

•.  bu  
tons 

Corn,  other  

tons.... 

tons... 

Wheat  

bu  

".  bu  

Rye  

^  bu  

:  bu  

Oats  

bu  

bu  

Barley  

.'  bu  

•  bu  

Buckwheat  

bu  

.:.  ;  bu  

Hay  

tons  .... 

tons.... 

Alfalfa  -.  

tons.  ... 

tons.... 

Oat  Hay  .*.  

tons.... 

,„,  tons.... 

Oats  and  Barley  ....'.  

tons.... 

tons.... 

Oats  and  Peas  

:  '.  tons... 

.tons,... 

Field  Beans  

'.  bu  

........bu  

Cabbage  

tons.... 

...^  •        tons.... 

Cauliflower  

;  

.-...'.  bbl  

.'.....bbl  

Brussels  Sprouts  

crates.. 

.-.  crates.. 

Apples  Bearing 

bu  

bu  

Apples  not  Bearing  

J  

POTATO  PRODUCTION  FOR  1911,  1912  AND  1913. 


Yew 

Varieties 

Acres 

Yield  per  acre 

Total  yield 

Early  

1911 

Late   



Total   

Early  

:.....  

1912           

Late    

.....*  :  

ToUl  

Early  .... 

.  

1913           

'.  -  - 

Late    

- 

Total  

;  •   -v^-^--^  

DISPOSAL  OF  1912  CROP 


Date 

Bushels 

Price  per  bu. 

Total 

Sold 

$ 

$ 

Seed  

Feed  

Home  use  

Total 



(Ave.)  

SPECIAL  EQUIPMENT 


Cost 

Value  1912 

Life 

Depredation 

Cost  of  repairs 

Planter  

...$  

...$  

...$  

...$  

Sprayer  

Digger.....  

Cutter  

Other  equip.  

_  

Total  

EXPENSES  1912 


Price  per  unit 


Total 


Rental  value  of  land 

Fertilizer 

Manure  from  preceding  crop.. 
Manure,  used  by  1912  crop .. 

Seed,  farm  and  bought 

Dust  for  cut  seed 

Copper  sulphate 

Lime  (form  for  spray) 

Insecticide  (kind) 

Carriers  not  returned 

Equipment  Rented 

Rental  value  of  storage 

Repairs  on  machinery 

Depreciation  on  machinery 

Man  labor 

Horse  labor 

Equipment  labor 


.tons... 
.bu.  ... 


hrs. 
hre.. 


Total 


SUMMARY 

Total  receipts  S .    . 


Total  expenses         .S 

Profit  1912  crop       $ 

Profit  per  acre         $ 


LABOR  ITEMS 


Date 

Acres 

Per 

HI. 

acre                           To 
h.         j        m. 

M 
h. 

Manuring.....  

Plowing,  Spring  

Plowing,  Fall  !  

Dragging,  times  

„  

Discing,  times  

Rolling,  times.  

Cutting  seed  

Treating  seed  

Removing  sprouts,  times  

Starting  sprouts  

x;  

Marking  





Planting,  machine..  



Planting,  hand  

Fertilizer..™  

Recovering,  times  



Weeding,  times  

Cultivating,  times  '.  

Hilling,  times  

- 

Spraying,  times  

Digging  and  picking  up,  (hand)  

Digging  and  picking  up,  (machine) 

Harrowing  after  digging  

Sorting  and  bagging  in  cellar  

Hauling  to  storage  

Hauling  to  market  

Hauling  from  storage  to  market  

Work  on  equipment  

Work  on  storage  

.\ 

Total  

"MISCELLANEOUS  FACTORS 

Manure.    Kind  used Tons  per  acre Source,  if  bought 

Where  applied Name  of  spreader,  if  used 

often  in  rotation Piled  or  spread Plowed  in  or  harrowed 

Value  of  residual  manure  on  potatoes,  1912  per  cent 

Plowing.    Depth  of  plowing .^ 

Seed.    Source Amt.  used 

Seed  Treatment.    Corrosive  sublimate.    Formalin.    Formaldehyde  gas.    Flowers  of  sulphur.    Formula 

How  treated •• 

Satisfactory  ? Consequent  injury  to  vitality  ? 

Starting  Sprouts.    Increase  in  yield  noted Increased  earliness  noted 

Cutting  Seed.    Amt.  cut Name  of  the  cutter,  ;f  any 

Satisfactory  ? Type  of  seed  planted  : 

1.  Small  whole 

2.  Medium  whole 

3.  Large  cut,  3  or  4  pieces 

4.  Medium  cut,  2  or  3  pieces 

5.  No.  eyes  to  piece 

Formula 

Source  of  P 

Ingredients  used 


How  long  cut  before  planted 
Fertilizer.    Amt.  per  acre 

Source  of  N 

Home  mixed 


Cut  seed  dusted 

Brand 

Source  of  K 

Amt 


.Price : 


DISPOSAL  OF  1912  CROP 


Date 

Bushels 

Price  per  hu. 

Total 

Sold 

$  

...$  

Seed  

Feed  

Home  use  

Total  _  

(Ave.)  :.  

SPECIAL  EQUIPMENT 


Cost 

Value  1912 

Life 

Depreciation 

Cost  of  repairs 

Planter  

...$  

....$  

....$  

...$  

Sprayer  

,  

Digger.....  



Cutter  

Other  equip  

_  

Total  

EXPENSES  1912 


Amount                              Price  per  unit 

Total 

Rental  value  of  land  

acres.. 

..$  

Fertilizer  

tons.... 

Manure  from  preceding  crop  

tons.... 

f 

Manure,  used  by  1912  crop  

tons.... 

Seed,  farm  and  bought  

...  .bu  

Dust  for  cut  seed  

Ibs  

Copper  sulphate  

Ibs  

Lime  (form  for  spray)  

Ibs.  

Insecticide  (kind)  

Ibs.  

Carriers  not  returned  

Equipment  Rented  .'.  

Rental  value  of  storage  

Repairs  on  machinery  

Depreciation  on  machinery  

Man  labor  

hrs  

Horse  labor  

..-  hrs  

Equipment  labor  

hrs  



;  

Total     

,  

SUMMARY 
Total  receipts          $ 

Total  expenses          $.. 

Profit  1912  crop       $ 

Profit  per  acre         $ 


LABOR  ITEMS 


Date 

Acres 

Per 

in. 

acre                            To 

h.         |        m. 

tal 

Manuring.....  

Plowing.  Spring  

Plowing,  Fall  

Dragging,  times  

„  

Discing,  times  

Rolling,  times.  „  

.v.  

Cutting  seed  .... 

Treating  seed  

Removing  sprouts,  times  

Starting  sprouts  

Marking  „  

Planting,  machine...  

Planting,  hand  

Fertilizer......  

Recovering,  times  
Weeding,  times  ".  

~i'.i 

Cultivating,  times  '.  

Hilling,  times  

i. 

Spraying,  times  

Digging  and  picking  up,  (hand)  

Digging  and  picking  up,  (machine) 

Harrowing  after  digging  

;... 

Sorting  and  bagging  in  cellar  

Hauling  to  storage  

Hauling  to  market  

Hauling  from  storage  to  market  

Work  on  equipment  

Work  on  storage  

Total 

"MISCELLANEOUS  FACTORS 

Manure.    Kind  used Tons  per  acre Source,  if  bought 

Where  applied Name  of  spreader,  if  used 

often  in  rotation Piled  or  spread Plowed  in  or  harrowed 

Value  of  residual  manure  on  potatoes,  1912  per  cent : 

Plowing.    Depth  of  plowing 

Seed.    Source Amt.  used 

Seed  Treatment.    Corrosive  sublimate.    Formalin.    Formaldehyde  gas.    Flowers  of  sulphur.    Formula. 

How  treated .• 

Satisfactory  ? Consequent  injury  to  vitality  ? , 

Starting  Sprouts.    Increase  in  yield  noted Increased  earliness  noted 

Cutting  Seed.    Amt.  cut Name  of  the  cutter,  'f  any 

Satisfactory  ? Type  of  seed  planted  : 

1.  Small  whole 

2.  Medium  whole 

3.  Large  cut,  3  or  4  pieces 

4.  Medium  cut,  2  or  3  pieces 

5.  No.  eyes  to  piece : 

Cut  seed  dusted 

Formula Brand Co. 

Source  of  P '... Source  of  K 


How 


How  long  cut  before  planted 
Fertilizer.    Amt.  per  acre 
Source  of  N 


Home  mixed ... 


Ingredients  used 


Amt. 


Price. 


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